2. Make sure you can see both, the Block List and Block Details.
3. Select Texture > Export Template.
4. In the Block List, find your NiTriShapeData.
5. In the Block Details, edit the Value for Num UV Sets so it shows 2.
6. Put the Value from Num Vertices into Num Match Groups.
7. Click all of the green arrows or recycling buttons numerous times.
8. Save your .nif.