Okay, I'm keeping this to one forum. (took a hint from multiple postings). Here's the reply I received back from Philips, it's put much nicer but still spells out to S.O.L.

Dear Njustus7,

Thank you for your enquiry.

The whole problem in this case is with the conversion of a Pioneer HEX
code into a valid Pronto HEX code. Both codes contain information only
the interpreter in the actual remote understands and can convert into a
valid Ir code. In order to make a Pioneer code compatible to a Pronto
one, you need the Pioneer command set, as well as you need to know how a
Pronto HEX code is set up. And this is only theoretical, as in practice
(and you know that from experience) it is almost impossible to get the
commandset or an explanation of the HEX interpreter from a hifi
manufacturer. So I am sorry to tell you that if Pioneer cannot provide you
with correct information, it is impossible for us to point you in a
direction for getting information on how to convert the different codes.

Kind regards,
Philips Pronto/URC European helpdesk