Search some of the old threads here regarding your application issue.
I believe it has been done. Not sure if it was XM or Sirius that was available.
I had initially looked into this about a year ago for my 06 HL with OE Nav.
I just never liked Sat. reception and sound quality in general in an urban area where I live, and never pursued it.
I believe that either the AM or FM button repeatedly pressed will provide a Sat screen when the kit is installed. It could be the old Solara or Camry Kit is what works .
One of these kits will crossover to several other Toyota Models with a Nav. or Digital display.
The 04 Nav equipped HL's are the same
schematically wise right thru the 07 HL limited's with the the same OE nav option.
LT