The other day a colleague of mine asked my for a favour to write a small function that strips the SIP URI from his caller list and redial list. At home he only uses SIP trunks to the outside world and therefore he always gets the SIP URIs into all lists.
Well, the result is the following piece of code that has to be copied into the gse script's Start block, and later on within the script, somewhere before the Connect To block you need to call the FixSIP function, best suited within a Insert Script Code block.
Feel free to use it where ever you like 
Sub FixSIP()
Dim sNumber
sNumber = StripNumberFromSipURI(PBXCall.CallingPartyNumber)
PBXCall.CallingPartyNumber = sNumber
PBXCall.PhoneCallListEntry.Number = sNumber
End Sub
Function StripNumberFromSipURI(ByVal sURI)
Dim sReturn
sReturn = sURI
If Left(LCase(sReturn), 4) = "sip:" Then
sReturn = Right(sReturn, Len(sReturn) - 4)
If InStr(sReturn, "@") <> 0 Then
sReturn = Left(sReturn, InStr(sReturn, "@") - 1)
End If
End If
StripNumberFromSipURI = sReturn
End Function