Hey,
Not sure if this will get you the results you're looking for but.... You could try a journal entry. Debit accounts receivable (you'll have to create a customer account for your vendor ie HomeDepot) and credit whatever the expense category was, enter the project/customer in the customer field. Then make a deposit for the amount from accounts receivable with the home depot (customer) account. It seems like a dumb work around to me but it will get that expense credit to show up in your project.