I had a similar situation with my Scientific Atlanta STB from Rogers Cable.
The remote uses a high freq (58Hz). I could learn the codes without any problems , but I could not get them to pass through the IRTRANS receiver and transmitter.
I ended up creating a translation table for it with a like for like input match to the the output and it worked.
It looks like this example:
--> rogers info
<-- rogers info
--> rogers channel +
<-- rogers channel +
I then loaded the table into the transmit unit and it works!
I have since mapped several different low freq remotes (38hz) to the Rogers codes successfully.
I was lucky to have ordered the Ethernet POE version with built in translation DB support.
Hope that helps,
Paul