The Pronto should work with the SKy+, no matter if its a box built by Pace or the newer ones built by Amstrad. These Sky+ remotes uses a normal IR-protocol and these remotes are designed by Universal Electronics (the company behind One For All and the worlds largest OEM manufactor for universal remotes), see also:[Link: indiantelevision.com]
The notorious Pace boxes who use IRDA are not the boxes for BSkyB but the cableboxes Pace produces for NTL and Telewest. Unless you buy an IR to IRDA coverter for these boxes you can not operate them with a Pronto. If I'm not mistaken only One For All produces universal remotes who can operate these IRDA-boxes (my 5 year old OneForAll URC-7560 doesn't have any problems with these IRDA-boxes, I can update code 1068 via modem and than it works).
BTW the correct Sky+ setup-code is on my OFA the SAT code 1175, but I don't think this code will be in the memory of the Pronto. However you can use the learning feature of the Pronto in order to operate the Sky+ box.