Deleted the original file from EFS, uploaded your file in Test mode with QXDM (files don't have the same content, so I got this idea). Now I have a SIM Connection. Will have to switch off test mode now and then to test if my car accepts the simcard. But it looks very good at this moment.
edit: yes the RSAP connection works with a premium FSE in my VW. But I don't know how stable it is. Had a test call and after that the bluetooth connection dropped and reconnected after bluetooth seems to be switched off and on. But could also be only luck...
for someone who also wants to test the necessary command for this xperia to activate diag mode is:
setprop persist.usb.eng 1
after that switch off debugging and enable it afterwards, now you will see 5 devices. the device with mi04 is the one you need for modem file...