Not sure quite what you're talking about what you can do is still use your Westpac account as well.
So what I do is have both Westpac and Etrade open and then I simply just do all my trades via Etrade :)
The ONLY disadvantage of using Etrade imho is that you have to have money in your account first before you can begin trading and you have to put a trading password in everytime you wanna trade (which can take a lil time when you're in a rush)......Apart from that, I'd recommend it over Westpac ANY day of the week and the BONUS 50,000 Qantas Frequent Flyer points are TOO GOOD TO REFUSE :)