Hi Daté,
workflow that you plan is very promising und a good use of XMP.
I can only help with the aspect of getting the FileInfo panel up and running.
First, please note that
CS5.x uses the folder
...\Adobe\XMP\custom file info panels\3.0\panels
and CS6 the folder
...\Adobe\XMP\custom file info panels\4.0\panels
If the panel is in the wrong folder, the panel is ignored.
Second, if the tab of the panel is shown but the panel itself stays empty,
it is very likely that you did not succeed in creating a "Flash Player Trust File" for the
user panel directory.
Please see the "XMP FileInfo SDK Programmer's Guide", page 53 on how to do this.
Only if the example with the single property is running you should go ahead and add your own properties.
Regards, Stefan