How do I concatenate a single field from multiple rows in BOXI 3.1 WebI?

Hi, 

I'm using BOXI 3.1 WebI and have a need to show multiple values of a column in a comma delimited list.  I tried using a horizontal table but if the list goes over the right margin it creates a new page instead of wrapping to the next line like we want.  I can do what I want in Oracle sql using the WM_CONCAT aggregate function but haven't found a way to do it in WebI reports.  Has anyone figured out a way to do this?

Thanks,

John Klein