diff --git a/common/proto/accounting.proto b/common/proto/accounting.proto
index 64ec40d..7165cdb 100644
--- a/common/proto/accounting.proto
+++ b/common/proto/accounting.proto
@@ -111,6 +111,13 @@ message PostJournalRequest {
   // creating. Must be empty when appending. Rejected when it falls at or before
   // the latest closed or approved accounting boundary for the profile.
   string accounting_date = 7;
+
+  // Convert this posting with the profile's own rate for the publication date
+  // instead of the ECB reference rate. False, the default, always uses ECB, even
+  // where a custom rate for that date exists. True requires one to have been
+  // entered: a missing rate is refused rather than silently converted at the
+  // official rate. Ignored when nothing needs converting.
+  bool use_custom_rate = 8;
 }
 
 message JournalLineInput {
diff --git a/common/proto/ecb.proto b/common/proto/ecb.proto
index 25279d3..7c8e34b 100644
--- a/common/proto/ecb.proto
+++ b/common/proto/ecb.proto
@@ -37,10 +37,14 @@ message PreviewEcbConversionRequest {
   // 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.
+  // Required. Profile whose rates apply. Only consulted when use_custom_rate is
+  // set, but always required so a preview names the books it describes.
   string profile_name = 5;
+
+  // Preview the profile's own rate for the publication date rather than the ECB
+  // reference rate. Must match what the posting will ask for, or the preview
+  // describes a conversion that will not happen.
+  bool use_custom_rate = 6;
 }
 
 // The conversion and immutable local ECB observation that would be used now.
diff --git a/common/src/proto/descriptor.bin b/common/src/proto/descriptor.bin
index 0e288a4..c57fd5a 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.accounting.rs b/common/src/proto/komp_ac.accounting.rs
index c038859..37e659e 100644
--- a/common/src/proto/komp_ac.accounting.rs
+++ b/common/src/proto/komp_ac.accounting.rs
@@ -28,6 +28,13 @@ pub struct PostJournalRequest {
     /// the latest closed or approved accounting boundary for the profile.
     #[prost(string, tag = "7")]
     pub accounting_date: ::prost::alloc::string::String,
+    /// Convert this posting with the profile's own rate for the publication date
+    /// instead of the ECB reference rate. False, the default, always uses ECB, even
+    /// where a custom rate for that date exists. True requires one to have been
+    /// entered: a missing rate is refused rather than silently converted at the
+    /// official rate. Ignored when nothing needs converting.
+    #[prost(bool, tag = "8")]
+    pub use_custom_rate: bool,
 }
 #[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
 pub struct JournalLineInput {
diff --git a/common/src/proto/komp_ac.ecb.rs b/common/src/proto/komp_ac.ecb.rs
index 82349c5..dc18e28 100644
--- a/common/src/proto/komp_ac.ecb.rs
+++ b/common/src/proto/komp_ac.ecb.rs
@@ -13,11 +13,15 @@ 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.
+    /// Required. Profile whose rates apply. Only consulted when use_custom_rate is
+    /// set, but always required so a preview names the books it describes.
     #[prost(string, tag = "5")]
     pub profile_name: ::prost::alloc::string::String,
+    /// Preview the profile's own rate for the publication date rather than the ECB
+    /// reference rate. Must match what the posting will ask for, or the preview
+    /// describes a conversion that will not happen.
+    #[prost(bool, tag = "6")]
+    pub use_custom_rate: bool,
 }
 /// The conversion and immutable local ECB observation that would be used now.
 /// No rounding is performed and no conversion evidence is persisted.
diff --git a/server b/server
index 4be8e7b..bb6fe4b 160000
--- a/server
+++ b/server
@@ -1 +1 @@
-Subproject commit 4be8e7b0a4e95e48220442717c20adfc51518fb6
+Subproject commit bb6fe4b65f508873ac73844017b44d1db25c8f9d