XML visibility proxy

[Scott Sanchez]

Can anyone recommend an open source web proxy solution for getting  
visibility in to an XML stream?  e.g to sit in the DMZ and act as the  
SSL end point for business partner connections... Giving me a hook to  
suck out the data and log it, scan it, etc before opening another SSL  
session to the "real" end point?

I could hack together a simple mod proxy solution, but there has to be  
something decent out there that's tuned for XML already.

Thanks,
Scott