Exporting tables with complex header with tabletools

Hello!

I'm having an issue and dunno how to solve it after many tries.

I have a datatable with complex header, but when i export it using tabletools, my complex header is gone (it exports only last TR element in HEAD)

What am I doing wrong?

here's the fiddle http://jsfiddle.net/laryro/bP2BJ/

How can I fix this?

Thanks!