Does winter sowing give you that much of a head start? If not, I'd recommend starting them inside four weeks or so before your last frost.
I've found that sowing in situ takes a long time for the seeds to germinate. They have an exceptionally hard coat and it'll take quite a while to soften it up before they germinate. They'll need to soften up, then get good and warm before they start growing. I normally nick the seeds then soak over night (sometimes longer) in tepid water. They germinate within a few days that way, then they get potted up once they get true leaves (into 4" pots). When the ground has warmed up and night time temps are above 50 or, preferably 60ยบ they go in the ground. Growth is very slow until the air temps are consistently warm and the ground temps are also.
rosebud, your vines should do great against your warm wall. I hope you have a great vine or two this coming year!
Shoe
