Header Modules Width

Hi everybody,

(sorry for my english...)

I have to put 2 modules in header:

Module 1 in Header_1 position (66% width) and Module 2 in Header_2 position (33%) width.

But Header_1 to Header_4 seems to be floating...
So when i put 2 modules in header, they are each 50% width...

Anyone has a solution for customize header width please ?

Thank you...