Bulk Billing process

We have not used this process yet, we bill each order individually. Does anyone have some helpful hints for us before we start? I have a number of questions, if anyone knows the answers it would be appreciated.
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[*]The screen gives you the option to print or e-mail the invoices, but not fax. Does anyone have a workaround for customers who like faxed invoices?
[*]When you choose to e-mail the invoices, does it select the e-mail address on the order, or the one from the customer record (the way the fulfillment e-mail does)?
[*]Has anyone customized the e-mail message that goes with the invoice/cash sale?[/LIST](PS - sorry about the multiple posts, I can't seem to delete them. I didn't realize that hitting the tab was saving the post as new{it certainly wasn't inserting a tab:p }