I know it is difficult to mod this. That is why Armed to the teeth is having so many issues, and the other dual wield mod doesn't work for a lot of people. If it were a simple fix, modders would have finished it off by now, but it's not simple. Let's hope Bethesda steps up and changes this.
Thanks Bethesda, ahead of time

OP
I think I have found a solution..... if you want your dagger to show on your hip along with your sword you need to have 2 of the same dagger in your inventory. I tested it last night, it wouldn't work with just a steel dagger and a steel sword and after a little thought I decided to put another steel dagger in my inventory, fav list. You then equip a dagger in your left hand and sword in the right, unsheathe, and then re-sheathe, remove armor / clothing and then re-equip armor / clothing and wa la you have a dagger on the same hip as your sword, which will remain there even if you switch out weapons( swap a bow for a sword ). The only time it stopped to work was when I change clothes / armor but all I had to do was repeat the process and the dagger showed on my hip again
Kinda svcks that you need to take up room with an extra dagger, but vanity has a price.
