This is the appropriate "canned" response that you should give, but my previous post, is the longer version 
Of course I do not have any affiliation with MB and do not speak for them.
Michael B.

Of course I do not have any affiliation with MB and do not speak for them.
Michael B.
Quote from MBT-Steve:
toby.......
My apologies for not responding earlier. It is not a cost issue but one of suitability. We at MBT are generally more conservative and feel it is potentially not appropriate to accept payment to fund an account that could be creating debt (credit card) for that customer. Obviously trading can be speculative so it is our feeling that a customer should have the excess funds available before they venture into trading. I realize there could easily be exceptions to this which would keep it more convenient for the customer however this is the conservative nature of our firm.
Regards,
Steve