It appears blockexplorer with a TradeHill deposit address does not yield an accurate balance.
Got an example?
As far as I understand it, deposit adresses do not show higher amounts if you just do trades.
You deposit 10 BTC --> Balance on TH: 10 BTC; Balance on the address: 10 BTC
You trade the 10 BTC for 100 USD --> Balance on TH: 0 BTC; Balance on the address: maybe still 10 BTC (as it is on an adress owned by tradehill and another adress might get "billed" on payouts)
BTC crashes and you buy 100 BTC for 100 USD --> Balance on TH: 100 BTC; Balance on the address: maybe still 10 BTC, maybe less.
I don't really get what you want to achieve... you can track how much you paid to TH over time accurately though.