I don't have a part number but I think this is a photo of what you're looking for. If this isn't the right cord, then I hope someone posts the correct one.
Also, this link gives you a great video on replacing the top. Around the 9 minute mark, I believe you can see the webbing. But watch the entire video. It's great.

I have to keep my hand on the top when raising or lowering the top. I have a broken cord and webbing on the passenger side. I can't see that it can be replaced/repaired without at least taking the leading edge of the top off. I'm still studying that. I think I'm missing the rear portion of the cord that is broken. I'm driving up to a wrench-a-part yard this week and try to get the cords off of a badly wrecked 2005.