I need help for my asset.dat

[Glorfindel23]

Hello, I introduce my problem :

I making a submod for my map (the goal of this submod is to add textures for the objects of my maps) but I've a little problem I've created a asset.dat of my submod but now I have two asset.dat
1 -> The asset.dat of my sub mod
2 -> The asset.dat original in the repertory of the game (The original)

My question is "How can I append my asset.dat to the original ?"

Help me please ! I search since one month but the problem persists...
(Sorry for my bad english)

My asset data builder is "Sy's AssetBuilder"