Yea, my so called clamp has no plastic snap fingers like the original Volvo part did. It is basically a cup shaped piece on the outside, with a internal star washer and some king of foam gasket on the face. I'm glad you told me that it didn't work even though you plugged the clamp into the firewall by itself first. I didn't do it that way and I was going to take mine apart and try that next approach next but not after hearing your story.

I hate to return things but in this case I will try. It is a crappy design and I see no way of getting a nut on from the firewall as it is way back in there. I hope the Volvo OEM part is better.