F5 LTM balancing by source port

Hello, colleagues!

We configured Source Address Affinity persistence profile type for Siebel application. But we have a BPM system that must be balanced not by source address.

One challenge is that we can't balance http request, because tcp sessions are established to one server, but http requests are balanced between two servers and the first one can drop session by timeout.

Could you give me explanation, can F5 balance sessions by source port for certain BPM server?

Thank you for your advice.