diff --git a/common/proto/ecb.proto b/common/proto/ecb.proto
index e388e66..25279d3 100644
--- a/common/proto/ecb.proto
+++ b/common/proto/ecb.proto
@@ -36,6 +36,11 @@ message PreviewEcbConversionRequest {
   // ISO calendar date (YYYY-MM-DD). Its meaning is selected by
   // conversion_context: transaction, statement, or decisive date.
   string anchor_date = 4;
+
+  // Required. Profile whose custom exchange rate table is consulted before the
+  // ECB observations, so the preview matches what posting into that profile
+  // would do.
+  string profile_name = 5;
 }
 
 // The conversion and immutable local ECB observation that would be used now.
@@ -56,6 +61,14 @@ message PreviewEcbConversionResponse {
   optional string rate_fetched_at = 13;
   optional int64 import_batch_id = 14;
   optional string source_endpoint = 15;
+
+  // Present only when determination_method is custom_rate. rate_date and
+  // units_per_eur then describe the hand-entered row identified here, and the
+  // ECB observation fields above are empty.
+  optional int64 custom_rate_table_definition_id = 16;
+  optional int64 custom_rate_record_id = 17;
+  optional int64 custom_rate_row_revision = 18;
+  optional string custom_rate_note = 19;
 }
 
 // Identify one logical money cell whose conversion history should be inspected.
@@ -102,10 +115,19 @@ message EcbConversionEvidence {
   optional int64 import_batch_id = 16;
   optional string source_endpoint = 17;
   string evidence_created_at = 18;
+
+  // Present only when determination_method is custom_rate. The hand-entered row
+  // that supplied rate_date and units_per_eur. The row itself stays editable, so
+  // the figures above are the immutable record of what was actually applied.
+  optional int64 custom_rate_table_definition_id = 19;
+  optional int64 custom_rate_record_id = 20;
+  optional int64 custom_rate_row_revision = 21;
+  optional string custom_rate_note = 22;
 }
 
 message ListEcbConversionEvidenceResponse {
-  // True when at least one evidence row for this cell used an ECB rate.
+  // True when at least one evidence row for this cell used a rate, whether it
+  // came from ECB or from a hand-entered custom row.
   bool has_exchange = 1;
 
   // Newest-first immutable history for this page.
diff --git a/common/src/proto/descriptor.bin b/common/src/proto/descriptor.bin
index bc4d217..0e288a4 100644
Binary files a/common/src/proto/descriptor.bin and b/common/src/proto/descriptor.bin differ
diff --git a/common/src/proto/komp_ac.ecb.rs b/common/src/proto/komp_ac.ecb.rs
index 0f485a3..82349c5 100644
--- a/common/src/proto/komp_ac.ecb.rs
+++ b/common/src/proto/komp_ac.ecb.rs
@@ -13,6 +13,11 @@ pub struct PreviewEcbConversionRequest {
     /// conversion_context: transaction, statement, or decisive date.
     #[prost(string, tag = "4")]
     pub anchor_date: ::prost::alloc::string::String,
+    /// Required. Profile whose custom exchange rate table is consulted before the
+    /// ECB observations, so the preview matches what posting into that profile
+    /// would do.
+    #[prost(string, tag = "5")]
+    pub profile_name: ::prost::alloc::string::String,
 }
 /// The conversion and immutable local ECB observation that would be used now.
 /// No rounding is performed and no conversion evidence is persisted.
@@ -48,6 +53,17 @@ pub struct PreviewEcbConversionResponse {
     pub import_batch_id: ::core::option::Option<i64>,
     #[prost(string, optional, tag = "15")]
     pub source_endpoint: ::core::option::Option<::prost::alloc::string::String>,
+    /// Present only when determination_method is custom_rate. rate_date and
+    /// units_per_eur then describe the hand-entered row identified here, and the
+    /// ECB observation fields above are empty.
+    #[prost(int64, optional, tag = "16")]
+    pub custom_rate_table_definition_id: ::core::option::Option<i64>,
+    #[prost(int64, optional, tag = "17")]
+    pub custom_rate_record_id: ::core::option::Option<i64>,
+    #[prost(int64, optional, tag = "18")]
+    pub custom_rate_row_revision: ::core::option::Option<i64>,
+    #[prost(string, optional, tag = "19")]
+    pub custom_rate_note: ::core::option::Option<::prost::alloc::string::String>,
 }
 /// Identify one logical money cell whose conversion history should be inspected.
 #[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
@@ -112,10 +128,22 @@ pub struct EcbConversionEvidence {
     pub source_endpoint: ::core::option::Option<::prost::alloc::string::String>,
     #[prost(string, tag = "18")]
     pub evidence_created_at: ::prost::alloc::string::String,
+    /// Present only when determination_method is custom_rate. The hand-entered row
+    /// that supplied rate_date and units_per_eur. The row itself stays editable, so
+    /// the figures above are the immutable record of what was actually applied.
+    #[prost(int64, optional, tag = "19")]
+    pub custom_rate_table_definition_id: ::core::option::Option<i64>,
+    #[prost(int64, optional, tag = "20")]
+    pub custom_rate_record_id: ::core::option::Option<i64>,
+    #[prost(int64, optional, tag = "21")]
+    pub custom_rate_row_revision: ::core::option::Option<i64>,
+    #[prost(string, optional, tag = "22")]
+    pub custom_rate_note: ::core::option::Option<::prost::alloc::string::String>,
 }
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ListEcbConversionEvidenceResponse {
-    /// True when at least one evidence row for this cell used an ECB rate.
+    /// True when at least one evidence row for this cell used a rate, whether it
+    /// came from ECB or from a hand-entered custom row.
     #[prost(bool, tag = "1")]
     pub has_exchange: bool,
     /// Newest-first immutable history for this page.