1. Ask somone to invite both your main and your alt in a raid groop.
2. make your main masterlooter
3. Enter the instance you wanna boost your alt in
4. Make a macro to Disconect your self by copy phasting the following script.
/script SendChatMessage("\124cffff80000\124Henchant:0124h[FreeDC]\124h\124r");
importand to put that extra zero behind it
5. you end up at the login screen log onto your alt, and enter the instance. now your in the same instance as your main.
6. logon to your main again "dont worry your alt wont be removed since your in raid" and clear till the boss you need the loot of.
7. log back to your alt and run to the boss. use the macro again to disconnect your self. Quickly logon to your main and kill the boss before your alt logs out of the game. hand over loot by using masterloot.
i used this way to get my alt the set: Embrace of the viper worked fine for me
im playing on EU live 2.3.3 server
Hope you could understand this caus my english aint great