Cipher in public key

[lomax]

I'm playing around a little bit with gpgshell 2.60 and gnupg 1.2.1-1
[under win2k]

I've found something that is confusing me.
in Gpgshell, i use as cipher-algo - 3DES.

when creating the keys,,, I'm not asked about the cipher-algorithm.
however, if I take a look, at my public key in PGP 8.0, it refers to
my key as type: DH/DSS, which is right and then: cipher - AES-128.

how is the cipher-algorithm related to the key? [I thought it's
independent from the key]
why is it showing AES-128? is there a way to put there something else?

any hints appreciated.
thnx,

-- 
lomax