Post moderation & author change

Hi,

I’m trying to do something like this:

1. I create a post using wp_insert_post( $post, $wp_error ); as draft via web form, where user id is also stored – I use it as an author field.
2. After the submission I want to publish this post via admin account.

Everything works great, but after I publish created posts the author name changes from the one used in submission form to ‘admin’

Is it possible to lock author name somehow ?

P.S. Sorry for my bad english 😉