"Yeah I saw the shirt with the HL3 logo. Visit Uberent.com for more info" Thats what I imagined, but he did handle very well, also Eka gave me hope.
Add SMNC as a non-Steam game. Name it HL3_0.0.1.325.exe (or something to that effect). From memory, most Steam games will happily pretend to be non-Steam games and work just fine.