Ok, took some pictures and as you can see the flexible foam tube that
is inserted just pull the seal down and push in the whole length of the
window seal and cut off.This will give the window a better seal.
Then we sealed the end off with some black
flexible super sticky stuff that BMW used on parts of the retractible
roof....we just picked a little bit here and there and filled the hole in
the window seal end..think anything that remains flexible and will adhere
to the window seal will worWk. Then glued a small pc of rubber to the end.
This in water tight now...we only sealed the front part of seal that sits into
the little cradle on both sides of car. The rear part of seal as shown is
not sealed shut showing the foam tube end...good luck