I have tried to build apps in PhoneGap Build using the package provided by the new "Create Package" function.
The result was not very encouraging. On Windows, the app will crash at startup, either complaining the there is no "cordova.js" or, if I remove the reference, because cordova-plugin-dialogs misses the reference. On Android I just get a white emtpy window and nothing happens...
Before investing time to understand what is going wrong and as I imagine I am not the only one facing such problems: do you plan any bugfixes or updates to make this process more smooth in general, or do you plan to publish some kind of migration guide addressing the most common issues?
One suggestion already at this point: for local plugins, instead of adding a comment to the xml file that PG Build will probably not find the plugin, the package creation wizard should include these plugins in the package.
Here is the doc page for the export and build process > https://software.intel.com/en-us/xdk/docs/build-xdk-app-with-phonegap-cordova-cli < for using both PhoneGap Build and Cordova CLI. If there are some things that are confusing or incorrect in that page, please let me know so I can update it and/or improve the content.
At this point, most people have had success building either with PhoneGap Build or with Cordova CLI. If you are having some issues there may be some adjustments to your app and/or build settings that need to be made (including modifications to your intelxdk.config.additions.xml file). Each project situation is different, so there is no single solution that I can offer that will fix your specific problem. The best way to get help is to provide specific details.
Regarding the use of private plugins, a reference to your plugin IS INCLUDED in the config.xml, the comment is IN ADDITION to that reference. However, if the plugin is truly private, and not just a modification of a standard third-party plugin, then that means that PhoneGap Build WILL NOT find it, despite the fact that there is a reference to it in the config.xml file. This is because it will search for the plugin reference in the standard Cordova NPM registry. If it is not finding it, that means you need to submit it as a private plugin, which is account-specific and not something we can do for you.
If you have a paid PhoneGap Build account then you can submit a private plugin to your PGB account and build with it. See this page https://build.phonegap.com/plugins/core for a link to that feature (which will only work if you have a paid account).
Otherwise, the other way to deal with a private plugin is to use Cordova CLI directly, instructions also provided in the link I provided at the beginning of this post. Create your CLI project and add your private plugin to that project. At the end of the article referenced above there are some ideas about how to link a CLI project to an XDK project, if you want to take that route (meaning you want to continue to use the XDK for things like App Preview and the Simulate tab). Otherwise, it may be simpler to simply export and leave the XDK entirely, once you have your CLI build system setup and working.