I do it without any problem. I update First to OS 4.2 and then to OS 4.5.
No problem at all. I also have DM 4.3. I dont need anything to fancy because the 8700 it is not the newest phone, so why DM 4.5???. Try this way.
The Girl Avtar???[b] Elisha Cuthbert!!! 8700g > 8310 (Thanks Horizon!!!) > 8320 > 9530 > 8900 > iPhone 4 > i717 > Passport