form_submit - Adding a class

[eluser]Shella[/eluser]
Hi everybody,
I'm kinda new with codeigniter and I'm looking to manage this form_submit styling.

Actually if I use:

Code:

form_submit('submit', 'Publish');

I return this:

Code:

<input type="submit" value="Publish">

What I can do to return:

Code:

<input type="submit" value="Publish" class="alt_btn">

Thank fools!

Shella