I'm using Uplink 1.30.
The manual says that the "VoIP Account Name" field is used as the caller ID presented to SIP when handling a Skype -> SIP call.
But it's not presented ... I've even done an Ethereal/Wireshark trace to check this. All that's sent in the SIP INVITE message is the SIP account number and domain.
Looks like a bug to me!