Thank you for the tutorial. Based on your tutorial I manage to create this: 

By reading the tutorial I manage to modify the BikiniTie bottom by removing the tie and make it into 2 tone texture. And I succeed, but I haven't finish it well. 

I also manage to import TS2 undies to TS3. It's taken from one of Bruno undies at MTS. It's not finish yet, just for preview.