To make a Custom XPath function available to other projects at design time, a two-step process is required. First, the plug-in project containing the function must be packaged by exporting it as "deployable plug-ins and fragments." This creates a shareable OSGi bundle (a JAR file). Second, this exported bundle must be installed into the TIBCO Business Studio "host repository." This action registers the plug-in with the design-time environment, making the custom function accessible to all projects within that instance of TIBCO Business Studio.

B. Installing directly into a target project is not the standard mechanism; this action does not make the function available to other projects.

C. Exporting the resource is only the first step. Without installing it into the host repository, other projects cannot discover or use it.

D. Adding the function to a single target project is a one-time use case and does not fulfill the requirement of making it available to other projects.

1. TIBCO BusinessWorks™ Container Edition Documentation, Application Development Guide, "Developing an XPath Custom Function", section: "Making the Custom XPath Function Available at Design Time".

Quote/Content: The documentation explicitly states, "To make the custom XPath function available at design time, you must export the custom XPath function plug-in project as a deployable plug-in and fragment and install it in the TIBCO Business Studio for BusinessWorks host repository." It then details the two steps: 1) "From the menu, click File > Export... select Deployable plug-ins and fragments" (corresponds to option E), and 2) "...on the Destination tab, select Install into host. Repository" (corresponds to option A).