Creating a self signed certificate - how do you set the 'storepass'

Hi, I'm trying to use the ADT to create an AIR 2.7 file, but it's the first time i've used the command line tool to build one and am having problems understanding the signing process.

I can generate a cert.p12 keystore file from within the flash IDE, and this asks for a password for the file (-storepass)

I can also use ADT to create a self-signed certificate from the command line, here you can specify the -keystore (cert location) and -keypass (password for the key in the store)

I cannot find a way of generating a self-signed certificate where you can specify both passwords though, one for the store (-storepass) and one for the key (-keypass).

This is a problem because when i go to package my AIR file using ADT it needs both passwords -storepass and -keypass before it can publish it.

Does anyone know how to generate a self-signed .p12 certificate and have control over both the keys...?

I have spent hours playing and searching now so may have the wrong end of the stick, could do with some help getting past this issue.

Thanks

Sean