one more question: is there a way to use additional keyring when needed ?

[Robert J. Hansen]

vl.pavlov wrote:
> but in thunderbird i still have no access to my key from stick

In Enigmail, I think you mean; Thunderbird itself has no OpenPGP 
support.  This may seem pedantic, but I don't think the Thunderbird crew 
would like to be blamed for things that are totally outside of their 
purview.  :)

The real question is not whether Enigmail can use your USB stick, but 
whether you can.  Plug in your USB stick and open up a command-line 
window.  Try to use your secret key that's on the USB stick.  If you can 
do this, then the bug is in Enigmail and it should be taken to the 
Enigmail list.  If you can't, then the bug is in your setup or your 
usage of GnuPG.

Let us know what happens.