just bought a clematis durandi, advice?

[AnimalBabe]

Hi all, this will be my first experience with planting a clematis. I'm in Northern Va and will be planting this next to my black lamppost in the front yard. I want to make sure I'll be planting it correctly and most of all, don't know what I should use to make it climb up the post. Any advice? I read someone's old post on here and someone suggested putting a thin trellis next to the post come early spring, and then removing it after the plant is pruned back. Would you suggest that, or some sort of wire around the lamppost, or something else?

Also, we have pretty bad clay soil, so I was going to amend it with half compost. Then I read to plant it so the top of the plant is about 5 inches below the soil line, and top that with a few inches of mulch. Sound about right?

Thanks so much!