signing and encrypting newbie question

[Mark Ivs]

Hello,
I am a very new to PGP. So please bare with my
question if it is really simple.

I am working on a project where I need to put some
signed encrypted files on an ftp site and our customer
will ftp it from there.

Here is what they want me to do. Please let me know if
it is do-able.

We have already  exchanged our public keys. Their
public key is added to our key ring. Before placing
the files on our ftp site for their retrieval,
customer wants me to SIGN the files with our public
key and ENCRYPT it using their public key. 

Please let me know if this is doable and if it makes
sense.  If so can some one how it can be done? I know
how to encrypt the files but I don't understand how to
encrypt and sign the files. Thanks a lot in advance.

For just encryption this is what I tried(it works):
gpg --recipient "XXX" --output $rootpath\\$filepgp
--encrypt $rootpath\\encrypted\\$file`;

-Mark

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