Hello Restivo,
I also debranded my phone with WoTan.
To Upload files to your w580i
Download XS++ 1.68
Place all the flash files (.swf) in the following path (Where your XS++ executable is located):
files_to_upload\tpa\preset\system\desktop\flash
Start XS++
Click on connect and connect your phone
Click on Customize
Go to Settings and click on BreakXS
Go to FSX and click on Start FSX.
Wait a couple of minutes and you're done.
Now you will need themes to use the flash files you've just uploaded.
Download and install TUG ZIP TUGZip - The Free Archiving Utility
Find a theme that you want to modify to use a flash menu on.
rename the file from XXXX.THM to XXXX.tar
Extract the files into a subfolder
Locate the .xml file
edit the file in notepad.
Locate the line: Sony_Ericsson_theme version="4.1"
Enter this after the line:
<Desktop_style Type="File" Source="XXXX.swf"/> where XXXX.swf is the name of the flash theme you wish to use.
Save and exit from notepad.
Highlight all the files you've extracted and right click on a file and click on add to archive.
Select the TAR format and zip the files.
Rename the zipped file from XXXX.TAR to XXXX.THM
Upload the THM to your phone.
Enjoy your new flash theme.