In Order to assign a particular icon (custom or not) to a particular category of service selector you must do the following:
1. Download and install a plist editor program like plistedit pro 1.5 from the Apple Software downloads.
2. Next launch Blueprint and goto the BP preferences off the top OSX Menu Bar. Locate the Show Debugging properties and select the checkbox to enable.
3. Now open your ipad user within inspector and locate the button that you want to show in a particular category. Highlight the button and locate the ~debugindentifier value and take not of it. It needs to be typed exactly (case sensitive) later on.
4. Open finder and locate your current logged in user (picture of a house) under places. Navigate to Library->Application Support-> Racepoint Media and expand the Racepoint Themes folder. Locate the theme you have in place for the particular mobile device with the proper version number. Right click on the theme and click show package contents. Expand the Containers folder and double click on the catagories.plist.
5. The catagories.plist file should now open in plist edit pro. Click the disclosure triangle top open the categories area. Expand the category you want your button to appear and then the Query triangle. Now highlight the Query area and click New Child. Enter the ~debugidentifier exactly as worded in step #3.
Your icon will now show within the category to which you have added it to.