We know that the RTD 215 uses the RCA IR protocol, and the function number that will turn the unit on.  We can probably guess the signals for the rest of the functions using the known signals for other RCA home theater systems.  Most universals send IR signals which will work individual components, but typically don't work with combo systems.

What's needed is a remote made by Universal Electronics which can be custom programmed on a button by button basis.  The cheapest is a Comcast DVR remote, usually available new on eBayfor $6 shipped.  Some RCA remotes can be custom programmed, so tell us which model you have.  If you have a cable remote, there is a better than even chance it is made by UEI, so mention the cable remote model also.

We can then tell you how to do the programming of each button (enter a 5 digit number).  Be prepared to spend an hour or so experimenting in case some functions are different than other RCA home theater systems.

And, the model number of the Sanyo?