Load Balancer - Port Redirection

I seem to be having some issues with the Load Balancer that I’ve not been able to figure out. I have some legacy code that is doing some odd stuff. I’m trying to use rancher to maintain a minor version of this software. Specifically, the software uses a non-standard port to connect to a mysql db. In the production environment, HAProxy is used to map this port to the correct server/port. Presumably, the load balancer can do the same thing (seeing as it too is HAProxy), but I couldn’t get it working. I added internal port maps, service links pointing to the lb, etc, but it would not connect. Finally, I went with just a straight HAProxy image with a pure custom cfg to get it working. Can someone help explain what I might be doing wrong?