"Ceiling Tivi Mount"

[dqninh]

Hi All,

I have bought the following ceiling tivi mount

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I will install it on my 2003 Thor Wind Four 5000 23A, which is based on the 2003 Chevy Express Van 3500.

My concern is, how can I find the "beam" above that plastic ceiling, so that I can screw to bolt into the beam, instead of driving the screw into the plastic board?

Any recommendation is greatly appreciated.

Many thanks in advance.