HI!
Yes it better to use hot air to help the glue to stick out because it's very fixed and i don't know if i can without that help.
Opened it sucessfull.
My problem was to find a replacement dock and it was difficult to find, and for those who need to replace the part 820-1794-A, can find the connector here:
http://www.aliexpress.com/item/Iphone-30pin-male-connector-Iphone-30pin-15-degrees-oblique-male-connector-Ipod-30pin-mobile-phone-connector/899116024.html
Hope i can help someone! Regards