Need help - disassembling HO Roco OBB 1045

Hello to all, maybe it’s a longshot, but I hope somebody can help me with this animal…

Roco Part-no. is 43530.

I want to disassemble the model to see if DCC decoder can be installed in the loco. I have tried from the below - no luck, 4 screws only hold wheelsets.

There is one plastic plate on roof I was able to remove, and there are two screws, but nothing happens when I unscrew them.

Can somebody help me take her apart? Thanks!

As most of us here are modelers of US prototype, not many have much experience with working on Roco equipment, but here are some links I found that might help further you along in your quest, good luck:

http://www.roco.co.at/index.php?id=1&L=1

http://www.roco.com/contact.aspx

http://www.eurorailhobbies.com/erh/roco.asp?gclid=CLWtubONgJQCFQ4vHgodN2MzWg

http://www.eurotrainhobby.com/index_cat.php/cPath/1_2.html

There is a report, but it is in german.

http://www.hp-pfeiffer.de/digi_umbau1/motorola/roco_oebb1045_ac/roco_oebb1045_ac.html