passing a recipient to gpg (sorry, once again, I forgot a word!)

Harald Katzer
Fri Jul 11 00:04:03 2003

Am Donnerstag 10 Juli 2003 23:28 schrieb Charly Avital:
> Gpg is asking you to enter *your* passphrase for the key you want to us=

for signing.
> Charly


I have generated 2 key pairs: foo and foo2
gpg wants to foo to sign the testfile and also encrypts the file for foo.
How can I tell gpg to use foo2's secret-key to sign and not foo's?