Its a generally question.
As far as i know there was just Issetea with his Sahrani Life and Chernarus Life modifications able to create a stat saving function und integrate it into his mission and the server. that means that all achievements were saved in a seperate database i guess. even after server was crashed, new started or completely down, all stats were saved in an account that the player made in the mission after joining the server.
a lot of ppl tried to steal issteas work or get behind the code/work about the stat saving. i cant believe that just issetea knows how to script it?! is there no one else able to made it?
PS: oops, sorry. Seems like its the wrong section. Pls move it to the right one