Fax from Email to a fax number with an asterisk in it

I know the standard procedure for sending a fax from email is to add the item you want to fax to the email as an attachment, then send the email to <fax number>@rcfax.com. This works great. Now I need to send a fax via email to a fax number with an extension. For example, 212-555-1212*82. How do I email to fax to that?