Unfortunately, I am not able to get rid of SOAP (different department is talking to our data) at this time, so I do need to work around it.

What I have done, following the link to the cookbook above, is added this to by dispatcher code:

BEGIN {
  package MySerializer; @MySerializer::ISA = 'SOAP::Serializer';
  sub envelope {
    $_[2] = (SOAP::Data
         ->name($_[2])
         ->prefix("TESTAPI")
         ->uri("urn:TESTServices")
        ) if $_[1] =~ /^(?:method|response)$/;
    shift->SUPER::envelope(@_);
  }
}
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This seemed to get me through the part that was stopping me. I now, however, am getting an error of System.Xml.XmlException: There is invalid data at the root level. Line 1, position 1. from the .NET WebService Studio client. Looking for what causes that now.