Microstran- Adding a double rectangular section to the section library to be visible in rendering

HI,

I am wondering if there is a way to add a double rectangular section to the section library to be visible in rendering in Microstran? I have tried to add a new section as (in Section Library Manager) Double-angle and Double C and it is not allowed saying tf, t is not valid.

Many Thanks.

Regards,

Shan K. Walgama, MIEAust | PhD
Structural/ Bridge Engineer
CDE Design Solutions Pty. Ltd.,

AU