I need a structural engineer

We are mounting a solar PV frame system on a concrete precast building with no suitable mounting points on the existing beams we are proposing to use steel beams sat on the precast beam to attach the mounting system to. The beams are 4.5mt apart and we have 70mm of space between the roof sheets and the beam.
I am awaiting the design team to supply the mounting distances and weight calculations would you be able to calculate the size of steel beam required to support this.
Regards
Andrew