diff --git a/fints4javaLib/src/main/kotlin/net/dankito/fints/messages/MessageBuilder.kt b/fints4javaLib/src/main/kotlin/net/dankito/fints/messages/MessageBuilder.kt
index 3f23635b..d34ddeb8 100644
--- a/fints4javaLib/src/main/kotlin/net/dankito/fints/messages/MessageBuilder.kt
+++ b/fints4javaLib/src/main/kotlin/net/dankito/fints/messages/MessageBuilder.kt
@@ -148,7 +148,7 @@ open class MessageBuilder(protected val generator: ISegmentNumberGenerator = Seg
 
     protected open fun signPayload(headerSegmentNumber: Int, bank: BankData, customer: CustomerData, date: Int, time: Int,
                                    payloadSegments: List<Segment>): List<Segment> {
-        val controlReference = Math.abs(ThreadLocalRandom.current().nextInt()).toString()
+        val controlReference = createControlReference()
 
         val signatureHeader = PinTanSignaturkopf(
             headerSegmentNumber,
@@ -168,6 +168,10 @@ open class MessageBuilder(protected val generator: ISegmentNumberGenerator = Seg
         return listOf(signatureHeader, *payloadSegments.toTypedArray(), signatureEnding)
     }
 
+    protected open fun createControlReference(): String {
+        return Math.abs(ThreadLocalRandom.current().nextInt()).toString()
+    }
+
 
     private fun encryptPayload(bank: BankData, customer: CustomerData, date: Int, time: Int,
                                payload: List<Segment>): List<Segment> {
diff --git a/fints4javaLib/src/test/kotlin/net/dankito/fints/messages/MessageBuilderTest.kt b/fints4javaLib/src/test/kotlin/net/dankito/fints/messages/MessageBuilderTest.kt
index 7e1bd9a6..7caf8018 100644
--- a/fints4javaLib/src/test/kotlin/net/dankito/fints/messages/MessageBuilderTest.kt
+++ b/fints4javaLib/src/test/kotlin/net/dankito/fints/messages/MessageBuilderTest.kt
@@ -10,7 +10,7 @@ import java.util.*
 
 class MessageBuilderTest : FinTsTestBase() {
 
-    private val underTest = MessageBuilder(utils = object : FinTsUtils() {
+    private val underTest = object : MessageBuilder(utils = object : FinTsUtils() {
         override fun formatDate(date: Date): String {
             return Date.toString()
         }
@@ -18,7 +18,13 @@ class MessageBuilderTest : FinTsTestBase() {
         override fun formatTime(time: Date): String {
             return Time.toString()
         }
-    })
+    }) {
+
+        override fun createControlReference(): String {
+            return ControlReference
+        }
+
+    }
 
 
     @Test