Support beam on paneling - securing drip edge

[Tacobob]

I am going to replace the plastic roof on the conservatory and thought, since the support beam is mounted on the outer cover panel, to place a drip edge underneath to prevent rain between the covers.

However, I have limited space since the support beam for the balcony is attached just above the plastic roof. See the picture. Do you have any tips on how I can seal it in the best way? Moving any of the support beams is not an option...