Apparently some people never get it ... the restraints of the TV signal itself do not allow for crisp detail. If you do the math on signal bandwidth, number of ACTUALLY displayed lines etc etc, then you'll find that the limit for distinguishable individual pixels (i.e. sharp detail) is around 360x240 resolution!
Nonetheless, fine tuning is of course found in ATi's control panel tabs, unsurprisingly on the TV properties page.