Captivate 3 selecting custom captions as preferences?

We're building a captivate (version 3) project template and we've found that an adobe supplied "custom" caption type is best to use for our needs (windows1.bmp).  We're designing the template so that multiple users can create captivate projects and all have the same caption types, fonts, etc.

When we try to save this custom caption type in Recording Caption Defaults under the Preferences, only 23 options are available in the drop-down list (i.e. Adobe Blue etc.) but there is no option to search for other caption types (unlike editing the properties on a caption which lets us select <Custom> which takes us to the file directory to choose one).

How do we choose this caption type as default?

P.S. I searched through the forum and one of the users mentioned "saving as" over the existing, i.e. Adobe Blue, but I'm not sure what they meant - do you have any ideas?