Thanks guys! Well, I've tried firefox approach, but:

-When using basic HTML gmail, clicking on attachment field launches the same dialog like in nokia client.
-When using modern desktop gmail, the same activity launches something like "last places" dialog, and it's not functional at all.

However, setting desktop gmail to basic html mode by default and using opera with desktop agent do the job.

I like the most qwazix solution. It's fast and simple. Thanks!