Ok, I see the share text button. There is also a save to eml/ pdf one. Share as eml or pdf would do the work, but its not there..
Also, as a workaround I was trying to find out whether you can do something with items that are placed in a dir (or in gmail- that a label), because this you can do fast in aquamail- copy to a folder. Unfortunetally cannot filter messages based on that.