From your post it appears that your STB has composite connections (Audio L, R and Video). But you mention 4 wires. I dont understand why there are 4.
Red, White connections are for audio and the Yellow is for video. Whats the 4th one for.
See if this works, on the STB find the Red, White and Yellow RCA female connections. These are the component outs. Using the RCA male-male wire, connect these to the corresponding Red, White and Yellow RCA female connections on the the TV.