There are several different templates, some of which have different functionality. We'll be happy to look into this. Can you open a support case and tell us which cover you used? Also in your case include a sample, time, date, with attachments etc.
I used the regular fax cover letter. I spoke with someone named Jo-Ed. Because I am the super Admin it would only show the Main office fax number and not the fax number that is assigned to my extension. Jo-Ed said it could not be changed, so I had to create a custom fax cover letter.