Correctly Entering Stock Transaction

[P. Croque]

Using gnucash 2.4 on Ubuntu 10.10 with the 'use trading accounts' option
turned on: I'm trying to enter the purchase of stock shares (say IBM)
denominated in USD that includes a commission (USD 9.99). My
'Expenses:Brokerage Fees' account is in CAD.

I enter the transaction in the IBM sub-account of my brokerage (the
account is in USD). I enter the splits so everything seems to
balance...except the expense in my 'Brokerage Fees' account is 9.99 (no
conversion to CAD occurred). I think it should be the CAD equivalent
(something like CAD $9.89) 

How should I be dealing with this? Create a separate transaction for the
commission? Create a separate 'Expenses:Brokerage Fees (USD)' account
denominated in USD? I would have to do that for almost all of my expense
accounts because I often buy things on trips to the US with US cash.

Any help would be greatly appreciated.

Thanks,

Randall