I don't have experience of the libraries you are using, but I wonder if the problem is to do with resource loading (rather than class loading) since you are not seeing a class loading exception.
In general, you may find it beneficial to create a PAR file or a scoped plan to contain your application bundles. That way you can export all the packages from which classes and resources may need to be loaded by the libraries you are using and dm Server will construct a Thread Context Class Loader making all those packages available for loading. It just depends how these libraries are doing their class and resource loading.
If that doesn't help, please let me know and I'll see if anyone else on the team has direct experience of these libraries.