Blender/Nifskope Help needed

[Guest oopaibir]

Hey there, I'm trying to merge two Nifs and I'm kinda at a loss. This is more or less a list of things I've tried already and I can't think of anything else, the two nifs I'm trying to merge are attached to the post.
If I try to copy the NiNode of one mesh into the other it won't work since then the part I copied won't be showing up ingame.

If I try to copy the NiTriShapes of one mesh into the other it won't work since they don't have the same bones which results in an error

If I put them both into blender delete one mesh's skeleton and all vertex groups and copy them from the other mesh and parent it to the remaining
skeleton it won't work since it will create two NiNodes.

These are my Blender export settings

 

 

arm.nif

upperpart.nif

[Guest]

Here's your merged model. Try to test it in-game and say how it works

arm+upperpart.nif

 

For It, I used only a Nifscope. Just copied the missed skeleton node parts into the Arm model, renamed them like it was in the upperpart model, and after, I start to copying another mesh parts, that I also renamed like it was been in the upperpart model.  

 

screenshot

[Guest oopaibir]

Works great ingame and I tried to merge a mesh myself with your explanation on how to do it and it turned out great.

Thank you very much!