It was also setting the content-length as a propertly on the JMS message when receiving a binary message.
I used the attached send.rb and recv.rb script to test sending a receiving a message with the content-length header set and it seem to work fine against the activemq trunk.
Closing issue out again as fixed on 5.0
script used to test reported error
When I send a STOMP (binary) message with a specified "content-length" header to the broker and try to receive it with another STOMP-Client then the second one does not receive this "content-length" header. I do not know where it gets lost but especially for binary messages this header is essential.