Generally, for audio devices, they number buttons are programmed in with discrete input functions. But since it is programmed for a generic Pioneer devices, you might not have all the ones you need for your model in the number keys.
If you post what setup code you are using for the receiver, it would be helpful. Assuming you are using AUX/1023 (or AUX/31023 if your remote takes 5-digit codes), try the following to program in the input select function to the TV/VCR key:
1. Press and release AUX
2. Press and hold SETUP until the remote blinks twice
3. Type 994
4. Press and release SETUP
5. Type 38789
6. Press and release TV/VCR button.
The remote should blink twice to confirm. Try pressing the TV/VCR button to see if works.