Editing Excel Template for XML Publisher

I created an excel template for a report using the Financial Report Template Editor.  I have been able to format certain things like adding a $ symbol and changing the negative amounts from - to ( ).  I uploaded the template and all works fine.  However, I haven't been able to add lines (_____ or ======) on certain rows without it creating multiple lines or misplacing the lines nor I have been able to change the negative amounts from red to black.  Any suggestions?

Also, as most of the formatting is being pulled from the fsg report row and column sets, will I need to create two distinct row and/or column sets to accomodate 1) the standard fsg formatting needs and 2) the xml formatting needs as the reports appear to produce different outputs?