Dimitri,
if you got it to work, withouth buying the source version ... that's ok with me. Just a few observations though:
* if you didn't buy the source version, then you are not allowed to redistribute any of the included software with your modified module
* i took a look at dnnExperts site map ... although it's a simple conversion of the dnn treeview skin object, the code does not contain any references to the dnn (bsd) license, and it's my understanding that in that case, the default copyright laws apply. So, before releasing a module based on work by others, please be sure you came to an agreement to do so .... otherwise you might be in violation of international copyright laws.
cheers,
erik