Hello Tina,
Where in QB did you populate those 15 custom fields? For instance did you use in on Invoice, Service Item, Estimate, etc? The reason I'm asking you this, is if you added the custom fields to different transaction areas in QuickBooks then those fields will be in different tables. So when you try to see those fields on one screen you would not be able to; if they are from different tables and the screen is based off of only 1 table.
Also, please take a look at the following post to learn a bit more on the technical side about how custom fields work: http://www.methodintegration.com/cs/forums/p/811/2943.aspx#2943
I'll wait for you to provide me some more information so I can try to replicate on my end. Also let me know the names you use for the custom fields so I can try it out.