Mesh Index Count

I am using cocos2d-x to run a 3D project, where I open STL files and have run into a problem, where the number of indices in the opened files exceed the unsigned short mark within a single mesh and the app just ruins the model, when showing it.

Is there a way I missed to fix this problem without changing a lot of types in the cocos2d-x source itself?
I tried the type change, but a lot of lagging and bugs accured - and the model was still not shown correctry…

I use this method to create a mesh:
static Mesh* create(const std::vector& positions, const std::vector& normals, const std::vector& texs, const IndexArray& indices);

It works, but only when the number of vertices does not exceed 65535, otherwise the model gets scrambled.

Can anybody suggest a good workaround or an actual way to fix this?