[html-formfu] force error on field?

[Josef Chladek]

hello,

I read that one should not use the DBIC::Unique constraint - so I eval:

eval {$row->populate_from_formfu( $c->stash->{form} );};

and then check if $@ has the message "Duplicate entry ... for key  
'email'"

how would I now set the error for the field 'email' in my form? or  
can I only use

$c->stash->{form}->force_error_message(1);

and use the string in form_error_message to show something?

thanks
josef