Nearly any remote made by UEI can be manually programmed to shoot the individual signals to teach the URC remotes.
Comcast and some other cable company remotes, OneForAll, some Radio Shack etc remotes can do this.
You could buy a RCA RCRP05B at Best Buy/Walgreens/Sears for $20, or a OneForAll URC-8820N at Sears for even less, if you don't have one of the above remotes.
Read post #4 in
this thread to see how to do it. If the list of functions there doesn't cover everything in your TV, post which functions you need, and the function number. I'll convert the function numbers into EFC form. Some UEI remotes take 5 digit setup codes, in which case prepend a 1 to the setup code: for example, instead of 0178 or 1265, use 10178 or 11265.