Unable to use batch mode to sign and encrypt a document with gpg

[Arnaud Paire]

Dear all,
 
I spend several days to make an automatic "sign and encrypt" with
gnupg-1.0.4
 
When I do:
    gpg -ase -r DEST myFile.txt
 
The soft asks me to promt the passphrase. I need to promt it automaticaly,
so I decide to use the batch mode :
    gpg --batch -ase -r DEST myFile.txt
 
But the soft answer me :
    gpg: can't query password in batchmode
    gpg: no default secret key: bad passphrase
    gpg: README: sign+encrypt failed: bad passphrase
 
So, I think I just need to know how to set a "default secret key".
I heard about a --default-secret-key option but it is not available in my
version.
 
I will be very glad if someone can give me a hand.
Thanks by advance
 
Arnaud.