Unfortunately, there is no way to make the Slingbox communicate in RF; most often, however, DirecTV boxes can indeed work in IR:
If this is not the case with your satellite box, you may want to ask DirecTV if they have any IR-capable options for you. It should also be noted that the remote codes listed in the Slingbox setup generally only work with remote address 1; if your DirecTV box is set to a different remote address, that may also be the cause of the issue.
Hope this helps!
The Slingbox Answers Forum Moderation Team