Custom sort function

["Surya Kiran Gullapalli" <suryakiran gullapalli gmail com>]

Hi,
I'm using a treeview with list store as its model. I want to sort some of the columns in the model. But by the design of my code, i cannot use the default sort functions. When ever i click on the header of the column, i want custom sort function (written for my code) to be called. How can i do that??

Thanks in advance,
Surya