[p@nDa]

i have finally done ... i explain how to so if some noob like me need this kind of thing it can follow my experience

1) add a new class in Additional CSS with attributes i would like to use ...

.lastpostby, .lastpostbyActive
{
	color: #ffffff;
}
.lastpostby a:link, .lastpostby_alink, .lastpostbyActive a:link, .lastpostbyActive_alink
{
	color: #ff8c25;
	text-decoration: none;
}
.lastpostby a:visited, .lastpostby_avisited, .lastpostbyActive a:visited, .lastpostbyActive_avisited
{
	color: #ff8c25;
	text-decoration: none;
}
.lastpostby a:hover, .lastpostby a:active, .lastpostby_ahover, .alt1Active a:hover, .lastpostbyActive a:active, .lastpostbyActive_ahover
{
	color: #33FF33;
	text-decoration: none;
}

2) simply add definition class="lastpostby" in the <div definition in the code ( in the template ) ...

<div class="lastpostby" style="white-space:nowrap<if condition="is_browser('ie', 6)">; float:$stylevar[left]</if>">
		<phrase 1="member.php?$session[sessionurl]find=lastposter&amp;f=$lastpostinfo[forumid]" 2="$lastpostinfo[lastposter]">$vbphrase[by_x]</phrase>
	</div>

see the photo attached for the change ...

that's all , but it was so hard figuring out how to do this , i really take long time to search for the specific help and at the end i tried on my own ...