Here it is how to "enable" uPNP in canola2:
1- first install fuse and djmount (https://garage.maemo.org/frs/?group_id=681)
2- mkdir /home/user/MyDocs/.sounds/djmount
3- djmount -o allow_other /home/user/MyDocs/.sounds/djmount
4- go to canola2 settings and activate it to watch in internal memory
5- refresh library
This should work, it's not a good solution, it's not fast but it works.
I have tested it with 8 gb of music, and it works great, not so slow.
If canola doesn't show the uPNP contents some "ls" in the /home/user/MyDocs/.sounds/djmount/ or a "find" can help.