You may want to buy the correct cable, so here is a message thread I put up recently addressing this issue and where to buy one for $5. The ebay link in the thread still works.
http://community.wdc.com/t5/WD-TV-Live-General-Discussions/WD-Live-to-SDTV-thru-A-V-Out/td-p/553403 It is the genuine cable – I bought one myself to have as a spare.