How to trap/map <Enter> to default button action?

[casper.bang]

I can't quite figure out how to trap/map <Enter> to a default button, say I want to invoke a "Save" button when hitting <Enter> inside associated editing fields. The doc mentions "...occurred on a form...", but does this mean I have to wrap my e.g. ToolStripButton in something under com.smartgwt.client.widgets.form.* ?

Thanks in advance.