Youre not gonna like it but
AdminCP > styles > your style > edit templates >
find and open : vbcms_edit_publisher
Find :
<div class="fullwidth" >
<div class="thirdleft">{vb:rawphrase published}</div>
<div class="twothirdsright">
<input type="radio" value="1" name="setpublish" <vb:if condition="$setpublish"> checked="checked"</vb:if> />{vb:rawphrase yes}
<input type="radio" value="0" name="setpublish" <vb:if condition="! $setpublish"> checked="checked"</vb:if> />{vb:rawphrase no}
</div>
^^ above code is the part that shows "published ()yes (x)no"
Then you could maybe either change the values on those two input boxes
and then instead of makeing them "radio" change it to hidden.. :D
or just comment it all out and put in
<input type="hidden" name="setpublish" value="0">
--- unfortunally dont think you can force publishing by default..
so it got to be modded.