Please some help..

Good morning,

I am trying to complete a logo  two days now but i cannot complete the transparency of the original logo. Can someone please help me out?


The original logo is Tecnifibre logo.Of course i have already vectorized all the letters, the outside of the logo and the white parts of it but i cannot find a roule in order to improve the transparency in the inside of the logo. I even tried with "trace" but the results are not good.

 Please help me...

Thanks in advance,

Renata