Trouble hemming kids' pants

(Belindi)
Well I finally broke down and bought a sewing machine. My kid, although
fitting into 18 month pants for his waist, can't fit the pants for the
length. So I bought the machine in order to hem his pants. Well the
trouble is that the opening at the hem is narrower than the swing arm so
I can't slide it over the arm and sew in a circle.
Does anyone know a trick to doing this?
---
I hate to bust your bubble, but, even with my freearms machines, I
cannot hem small children's pants/jeans--the legs are just too marrow to
fit over the freearm.
I wind up sewing them just as the other posters have described: turn
the hem up inside the leg tube, and slide the open end of the tube under
the needle.
This does mean thet you have to turn the leg several times to stitch
all ther way around the hem.
Cea