Which model of the PACE STB do you have. Different models will have different needs.
It's the remote control signal that causes the compatibility problems as that uses IRDA to transmit commands to the STB on some of the PACE boxes, whilst some more modern STBs use a more standard IR signal.
The Digisender system details can be found here :
http://www.digisender.net/_Europes_N...r_Company.html
You would probably need the Digisender Gold DG400