Encrypted volume - how?

[Norberto Meijome]

Hi all,
I'm looking for a way to recreate the functionality of PGP Disk (under 
Win32). Basically, create an encrypted file, which contains a filesystem 
which can then be mounted in any mount point.

I know I can use GELI in FreeBSD 6 - as I understand, it performs the 
encryption at the partition level (the whole partition is encrypted). 
I'd like to be able to simply unmount my 'secure volume', and be able to 
back it up as a whole, or move it to another computer without having to 
repartition the destination. I think GELI wouldn't be good for this.

I think I've read somewhere that you could use openssl to generate an 
encrypted volume and then mount it. I searched for a while and can't 
find any reference to this. Does anyone know how to do this with 
openssl, OR any other tool ?

thanks in advance,
Beto