diff --git a/src/main/java/com/solab/iso8583/IsoValue.java b/src/main/java/com/solab/iso8583/IsoValue.java
index 8ebc77c..195cde6 100644
--- a/src/main/java/com/solab/iso8583/IsoValue.java
+++ b/src/main/java/com/solab/iso8583/IsoValue.java
@@ -83,8 +83,9 @@ public class IsoValue<T> implements Cloneable {
 				} else {
 					length = value.toString().length() / 2 + (value.toString().length() % 2);
 				}
+            } else if (custom instanceof CustomBinaryField) {
+                length = ((CustomBinaryField<T>)custom).encodeBinaryField(value).length;
 			} else {
-				//TODO special encoder, NO strings
 				String enc = custom.encodeField(value);
 				if (enc == null) {
 					enc = value == null ? "" : value.toString();
@@ -130,7 +131,13 @@ public class IsoValue<T> implements Cloneable {
 			}
 		} else if (t == IsoType.LLBIN || t == IsoType.LLLBIN) {
 			if (len == 0) {
-				//TODO customfield binary!
+                if (custom == null) {
+                    length = ((byte[])val).length;
+                } else if (custom instanceof CustomBinaryField) {
+                    length = ((CustomBinaryField<T>)custom).encodeBinaryField(value).length;
+                } else {
+                    length = custom.encodeField(value).length();
+                }
 				length = custom == null ? ((byte[])val).length : custom.encodeField(value).length();
 			}
 			if (t == IsoType.LLBIN && length > 99) {
@@ -302,6 +309,10 @@ public class IsoValue<T> implements Cloneable {
 			if (value instanceof byte[]) {
 				outs.write((byte[])value);
 				missing = length - ((byte[])value).length;
+            } else if (encoder instanceof CustomBinaryField) {
+                byte[] binval = ((CustomBinaryField<T>) encoder).encodeBinaryField(value);
+                outs.write(binval);
+                missing = length - binval.length;
 			} else {
 				byte[] binval = HexCodec.hexDecode(value.toString());
 				outs.write(binval);