If you have a create button on the left it needs to have style:
float:left;
for the div on the right to float to the right use:
display:inline;float:right;
NB the display:inline stops the break or space before the div .
underneath both of these have an empty div with style:
width:100%; clear:both;
In Xpages xml:
<xp:div style="float:left;">left hand</xp:div>
<xp:div style="display:inline;float:right;">right hand</xp:div>
<xp:div style="width:100%; clear:both;"></xp:div><!-- this clears the line -->