Yes you can do this very easily.
I am not sure the exact menu format as I am in Europe and we use SCART rather than RCA. However, I am sure the principle is the same.
When you do a timer recording, you enter day, start time, end time in first three columns. The next column (I think as I am doing this from memory) is recording source (probably defaults to tuner). Press ok, on this column, and you will have option to select sources other than tuner.
It should be well explained in the manual.
Please be aware that some satellite shows are copy protected (use macrovision I think) - typically "pay movie channnels", and may not record (you can hack the 5005 to remove macrovision limitation).