Edit function for comments

hi. i have a problem.. with edit comment in blog section.

in blog section there is only delete function. i need edit function for comments. 

so now i'm trying to adapt group discussion's comment edit function to blog.

but it's not easy for me. :(

i looking some other's work. but there is only this ticket... 

http://trac.elgg.org/ticket/765

there is noting, but date...

now i can call previous comment by edit function with some code editing but i can't save adjusted comment. 

Thanks for any help :)