Mobile 5.5 introduced support for multiple JDE's and to help facilitate this we created the buildprofiles.xml file which contains build profiles for each JDE version you want to support. The file is stored in the same directory as the build.xml.template (\Library\BlackBerry\templates folder under the Mobile Architect install directory).
This example shows the build profile for v4.2 of the JDE. Notice the property elements. These elements allow you to override the same property in the build.xml.template during a build. In the snippet, the "path" property will replace the "path" property in the build.xml.template when a client system is built using this 4.2 build profile. Any property in the build.xml.template can be overriden in this way.To support the Java ME Platform SDK 3.0, add a property element to the appropriate build profile and set the name attribute to "wtk_home" and the element content to the SDK 3.0 install path as shown in the snippet. This will override the "wtk_home" property in the build.xml.template.
You are now ready to build your BlackBerry customizations.