Flex :: Setting The Correct Sort Function At Runtime?

Using Flex 3.2, I have a object which extends a TitleWindow. In this TitleWindow I have an AdvancedDataGrid.

On creation of this object, I pass it 2 lists, one full of data to display, and the other I pass an array of column definitions. This allows me to, at runtime, create the correct columns and define the correct display attributes for each column (e.g. booleans will show up as checkboxes, and dates are formatted in a specific format (coming in from an XML feed in a variety of STRING formats where nulls are a possibility)

The problem is that the default sort, being based on string, doesn't work 100% of the time and even when the format is one that would be sorted nicely, it fails when nulls are involved.

The above problem would be easily solved using a sortCompareFunction, but the fact is when you set the sortCompareFunction of the column, it seems to require you to hardcode in the column name into the function.

for reference here's the function I'm using to create the columns:

private function setupGrid():void
{
var localcols:Array = new Array();

[Code].....