The easiest fix to the problem is to just drill a 2" hole in the middle of the K plane for the strap to go through. I'm just kidding, please DO NOT do that.
Seriously though, I think you will be OK to run the strap around the tab. I don't think it will hurt anything. I did it for a few years on my 28 Pantera and just padded the strap where it contacted the tab to prevent it from rubbing. I found that the fuzzy seat belt wraps work well for this job. You know, the ones you see in all of the automotive stores that are supposed to pad your neck to keep the seat belts from rubbing.
Look at the tension on this strap/tab after we got whacked while making a right hand turn. This strap was under extreme tension after the accident and it didn't do any damage to the tab. After experiencing this, I personally don't think you will have any problems with the strap going around the tab for normal trailering conditions.