To create your own Firefox Sync server you need this file -> click. If file is not accessible try this or contact me.
( There is a contact form somewhere here )

So when you got all the needed files click away to your NAS station.
First make sure that you have installed myphpAdmin and mySQL is enabled. ( You can get those in Package Center under available tab )
After that log in to your myphpadmin console and create new DB with name FFsync ( or something else )

Computer config:
Notebook x company
Intel Core I5  x64!!!
1x 500GB disk
1x 1TB disk
Started to install Debian to do some tests on linux. Created new VM, appended Debian amd64 ISO file and stated VM.