If you want to mess with the texture matrix then you have to multiply it with a translation matrix (to bring it's center point to 0,0), then by rotation matrix and another translation matrix to get it back in position, but if you're transforming not a lot of points it will be faster to just rotate texture coordinates by hand.
X:= X ?¢_" CenterX;
Y:= Y ?¢_" CenterY;
NewX:= X * Cos(Angle) ?¢_" Y * Sin(Angle) + CenterX;
NewY:= Y * Cos(Angle) + X * Sin(Angle) + CenterY;