ANSI File through ESB

I’m working on a solution that expose WCF on-ramps to process some messages into ESB (BizTalk 2010), this receives a SOAP message and attaches some itineraries.

The problem resides in the client trying to send SOAP body with ANSI code-page and those aren’t being processed because ESB expects UTF-8 (in WCF binding and IIS application).

My logic says that the problem needs to be solved on the caller rather than BizTalk, is this right? I’ve been told by the client that they can’t make any chances on the request since its ISeries (but i don’t knoe anything about it)

Is there a way we can process UTF-8 and ANSI in the same On-Ramp? Any ideas, I’ve tried creating custom component as a test to force the encoding but the problems reside more on IIS layer than BizTalk layer.

Any advice will be helpful

Thanks