Anyway, is there ANY way to get steammanager to work in XP?
No, there definitely isn't. It's built on the native Windows 7 firewall (it doesn't work with third-party firewalls), and relies completely on features of it that aren't in the basic XPSP2 firewall.
As an alternative to Angus Wolfcastle's Steam Manager, you can try Steam Limiter
, which works on WinXP/Vista/Win7, which I wrote since I happen to have an XP gaming box myself. It's independent of any existing firewall, as well, and should just install and work out of the box with no configuration.
I'm based in New Zealand and although I wrote the code for this, the rules for Australia that my system uses actually come from Steam Manager; Angus looks after lots of threads on the Whirlpool forums to try and devise the best lists of servers to use for various ISPs in Australia and so we coordinate to keep our rules in sync. So, if for some reason you can't use Steam Manager
should work for you.