At the moment, to start with USD instead of BTC is only possible manually.. by turning off the $reset_data; editing the file: fakegox.txt USD balance and setting an "ask" on file last.txt, (now placed in the todolist the $fake_usd_balance, this feature will be available soon)
Currently, in my mtgox there isnt any btc, I only own several USD. Does it mean it will loop forever like this unless I buy BTC and change the value you mentioned to the value I spent?