Sendmail on CentOS 6, with SRS

I do some mail forwarding, but I'm also a big fan of SPF; I'm aware that I have a problem.

While my mail server was running Centos5, I was using pysrs as a milter, and it worked well - but it hasn't been updated for python 2.6 (much less the 2.7 that C7 will require) - so I reluctantly had to stop using SRS when I upgraded to C6 (which I needed to do for DNSSEC support, before anyone suggests going back to C5!).

Does anyone have SRS working with sendmail in a C6 environment, and how do you do it? Or should I bite the very painful bullet and change MTAs to one that more directly supports SRS?