hifi-remote.com has an upgrade for a RCA 20F510TD which is TV-DVD combo unit. It's a similar model number.

It uses the Konka IR protocol, which is pretty rare. The TV section responds to device 2, while the DVD responds to device 6. If your unit uses similar codes, I suppose it would be not too hard to find the device number for the VCR section. It is very likely that the buttons like Vol+/- use the same function numbers for all three device numbers.

The remotes that I know about are made by UEI, and the only UEI remote available in the US that can shoot Konka is the OneForAll URC-8820N, and it can only send out device 2 (the TV section). The remote is less than $20 at Sears. In order to load in device 6, and to find the mystery device number for the VCR, it would be necessary to buy a flash JP1 cable ($29) or to make one yourself if your computer has a serial port.

You could also imagine getting Logiitech to load Pronto Hex for the TV and DVD sections, since we already know those IR signals. It might be difficult to get them to take part in multiple loads of Hex codes while you look for the VCR device number.