Adding Java executables to PAM r31 Mod menu

I've been using the PAM R31 mod since it's release and recently encountered a situation I have not been able to resolve by myself. So, I'd appreciate suggestions. I have two questions:

1 - You can add other application that are not in the PA directory format to the R31 menu using the 'Options - Add an External App' menu item. But the dialog box only displays .exe files. I have been able to enter *.com or *.jar to the filename box and display (and add to the menu) other files. However, is it possible to add these as options to the 'Files of Type' list to make it easier for less experienced people to use?

2 - While the machine I am using for testing does have Java installed, I can't expect other machines to have it. I do have Java on my USB drive. Is there any way to always select the PA Java installation when executing a Java program? Does '/PortableApps/Commonfiles/Java/bin/Java.exe {programname.jar}' work, or do you recommend another solution?