In WDL file:
Code:

material mat_twoside
{
    effect = "twoside.fx";
}


In "twoside.fx" file:
Code:

technique twoside
{
    pass p1
    {
        cullMode = none;
    }
}


It's 1am, so hopefully I didn't have any typos...

xXxGuitar511
- Programmer