sendmail forward how to?

[kursik3]

Hi all.

There is one mail box from which I want to do the forward on other box.

user1 at myserver.com  ----> any at anydomain.com

But I want to leave also letters in the first box.

I have created a file /home/user1/.forward and have written there any at anydomain.com

The forward works, letters leave on any at anydomain.com, but they do not remain in user1 at myserver.com, and I want that remained.

How to resolve this problem? 
Thanks.