[COLOR=DarkOrchid][SIZE=3][FONT=Comic Sans MS]You are going to be knitting in the round minus the sts on the holder. However you need to close up the gap those thumb sts create by CO one st when you reach that.
Just CO one st using either a knitted cast on, cable cast on or backward loop cast on, insert your needle into the next st on the hand, give a tug to snug up all the sts on the needles and continue to knit in the round.
What you are doing is closing up the gap made by the eleven sts on the st holder and continuing to knit in the round to finish the mitten. After you finish the top of the mitten, you'll go back and put those live sts on needles and knit in the round to finish the thumb.
This tutorial might help.