Here's the progress:

First I looked into everyone's advice, and my brain hurt. Note, it was all valid and good advice for a full blown and fully compliant SOAP server. However, this is for a limited and specific use. I knew there had to be a simpler solution... and I finally found it! In fact, it's so simple, I can't help but wonder why it isn't in the documentation. You simply add (before you instantiate the object):

$SOAP::Constants::DO_NOT_CHECK_MUSTUNDERSTAND = 1;
[download]

Yeah, my eye is twitching, and I'm giggling with glee that it was so simple. Grep was my friend here.

Thanks folks, you're awesome.