Asking the gate agent probably won't help. A Ryanair gate agent appears at the gate a few minutes before boarding starts, and there is simply no time for anybody to contact the captain in advance to tell him about your inquiry. In fact, a Ryanair gate agent always seems to be to be in a hurry to do the boarding as quickly as possible, there is no time for anything else.
Asking the cabin crew during boarding to ask the captain is probably more realistic. Showing them your company ID card will probably help, too. But of course, it depends on the company you work for. Last september I tried to get the jumpseat on a Sabena flight. Unfortunately, there was still "Swissport" written on my ID card, and of course there was no chance... But if you do not work for LH, I'm sure the name of the company won't be a problem