Need small help with menu editor

[vdr1981]

I'm trying to add few extra equipment slots to ingame damage menu but i struck unsolvable problem, en least for me...

By default , only 10 slots can be shown per each page in damage menu and this is controlled through GUIPlaceHolderIndex=[number from 1 to 10] defined in submarine UPCGE file. Each number biger than 10 will give instant CTD soon as mission starts...

So, i took menu editor, opened Page Subsystems/Group/Subsystems and , as expected, there were only 10 entries/controls. (Left PlaceHoledr1-5 and Right PlaceHolder1-5)



Then I copied one default entry to create new one (Test PlaceHolder1) and then I tried to set GUIPlaceHolderIndex=11
I was sure that this will work, but no...Again, soon as i load a mission, CTD...

So far i know this, the game still doesn't know that new entry with new ID is created and that's the reason for CTD. This is important because if I give to new entry an ID of some default entry, then new damage slot will appear in game but default won't...

Does anyone actually know what's going on here or where I'm making mistake?

Tnx in advance...