Help with modifying Budget Report

[ChrisW]

I'm a new user of GnuCash v2.0.4, very nice bit of software. Thank you.

I am trying to create a new report based on the existing budget report
but modified so that the text in the "Actual" column is green when <= to
the budget figure and red when > budget.

I can successfully load & run my new report using the "config.user"
method but I am struggling on how to change the code to format the cells
in the "Actual" column to be the required colour.

I have searched the achives without success so...
...any help gratefully received
e.g.
Has anybody written such a report already?
What gnc: functions should I be looking at?