wheelchairs with headrests....raincovers?

[midorimum]

my 3 year old son got his first wheelchair today, a sunrise medical quickie zippie ts in blue, very nice and folds quite small.

my problem is that he has very poor head control so it has a headrest fitted, i had purchased a few wheelchair poncho type things then realised they would need to go down his back rather than down the back of the chair and the cushion would get wet.

is there such a poncho that has a space at the back to thread the headrest pole thru so that the poncho covers the back of the wheelchair or are they all over the head type.

wondering if i will have to get the scissors and velcro out and get creative with the ones i have?

OR

do you think one of those universal framed raincovers you get for buggys would fit onto the wheelchair somehow or would that just look quite lame?

yep. Able2wear does one here
Has two slits for the wheelchair handles to go through. I stick the headrest through one of them. Seems to work just fine. But they may have something better.

thanks S i knew you would know!
i emailed them to see which one would be best, thanks again!