I sent a msg to the eBay seller selling the part which claims to be a service centre and they told me to resolder the part on is very difficult. I had asked how many pins and how far apart they were spaced.
Thus, I would recommended that 99% of you pay for it to be done by a service/repair centre.
Also, if you are going to use a micro sim adaptor, try to make sure that the edge on which the SIM reader pins catch and break on is covered with something like sellotape, or even make a template of the adaptor with paper/very thin card and glue it on top firmly so that the edges (of the paper/card) themselves do not lift up (to catch on the pins!). This may help to stop it catching, but obviously remember to cut a piece out in the middle so the SIM card can still be read!
If you feel I have helped in anyway then please click the THANKS!