Sort Expression - Custom Code

Hi,
I have a report that needs sorting on a column that is calculated. however, the calculation is so complex (iterative calculations) i've had to do that within my custom code. I am getting the results back well and good but i cannot perform a sort based on that.
My problem is: how do i write a custom sort expression function that will direct the column to sort my table based on say the value(s) returned from that function. I want for example:




Code Snippet
Public Function mySortExpression(byVal myIDorWhatever as Something) as CustomSortableExpression

' Perform some calculation
' Return some value(s)/array or anything that the column can appreciate and sort the table accordingly with
End Function




then in say the Interactive Sort Sort Expression, i'll have the code:



Code Snippet
=code.MyClass.mySortExpression(myID)


I hope i've made myself clear enough.
Cheers