How to Add new ad location ?

[6oct]

iam traying to add a new ad location. i have edited ad_locations_vbulletin.xml and added new ad tag with required spec .
<location key="testad">
<cp_width>361</cp_width>
<cp_height>52</cp_height>
<cp_xpos>105</cp_xpos>
<cp_ypos>150</cp_ypos>
</location>

when i go to my admin cp and ad management the ad is added correctly and the template is created in ad locations template group with name ( ad_global_testad )

finally i have edited navbar template adding {vb:raw ad_location.global_testad} after other ads

{vb:raw ad_location.ad_navbar_below}
{vb:raw ad_location.global_below_navbar}
{vb:raw ad_location.global_testad}

but i couldn't know what iam missing ? the new ad is still not displayed

is there any steps i have missed or any thing wrong i have done ?