Hi
Correct, unable to attach to supplier.
However, you do have the option of adding different tax codes.
Left Side Bar>Taxes>Add tax top right>Tax Rate>Fill in Tax Name, ie HST ON (13%)>Fill in description ie. Ontario HST - once you click purchases the tax rate will come up where you can enter the 13%. In this case, you would also choose liability and ITCs so when you post the expense receipt, and use your newly created HST ON 13% tax code it should show up on your ITC report as being paid on purchase.
Does this help you?