I wish we could be of more help, but we're experts in SOS and not experts in proxies. There are too many of them. The ISA configuration info we have was provided by an SOS user a few years ago, and may well be out of date.
The basic principal is that there needs to be a clear path for TCP/IP traffic both ways between SOS Client and SOS Server on the designated port (8880).
It might be helpful to try the "telnet test" where you attempt to telnet from the client machine to the server machine on the SOS port.
Open a cmd prompt and type:
telnet <servermachine> <port>
For example, to telnet to our demo server:
telnet sos.sourceoffsite.com 8888
If the connection succeeds you'll see a "200 Protocol-Version . . . etc" message. If the connection fails, then most likely the SOS client won't be able to connect, either.
With this information, you might be able to contact Microsoft or a Microsoft newgroup for specific information on how to configure an ISA proxy for TCP/IP traffic on a specified port. There's a good possibility that if you can get the Telnet connection to work, SOS would work, too.
(note: Are you using port 8880 as the secure or unsecure port? I'd suggest getting the connection to work first on the unsecure port, as that eliminates any complications with encryption keys, etc.)
Problem setting connections
Moderator: SourceGear