U1 music shows unknown artist, how can I make it recognize m4a files?

I am in the process of uploading my music library as a backup to U1, but I figured, why not also enjoy Ubuntu 1 music on my iPhone?

With a few difficulties to start, the upload is now in progress, but I've noticed that there is a huge percentage of files in the unknown artist folder, and I believe it is all of my m4a files. They play fine, but without any information.

Coming from an iTunes background, and having bought the majority of my music on the iTunes store, I wonder how I could make this work, easily?

I am on Maverick (afaik), but About Ubuntu shows 11.04. I use Banshee as my music manager, and I monitor my sync using Ubuntu one preferences, ubuntuone-indicator and magicicada.

The total file size of my music folder is 38.9GB.

Thank you for your help!! And apologies if I couldn't find a thread where this was already covered...

EDIT:

The Maverick/11.04 issue is a known bug, and I've seen it here: Why documentation says release is 11.04 instead of 10.10

If you'd rather not want to wait for the m4a support, you can help yourself out using soundconverter. I followed the instructions here: How do I convert music between formats and keep its metadata? It has taken AGES, but so far I am happy with the results... Note that you will need to install mp3 support in Soundcoverter, I stumbled accross it and install was very straighforward! Oh, and it does only convert m4a's that are not password protected, which I'm guessing will be mostly m4p anyway.