[al3bed]

ok, try this:

open 'postbit_lagecy' template find:

<!-- message -->

above it add:

<if condition="$post[postcount] == 1"><div><div style="float:right; margin-left: 5px;">$ain_adsense[id]</div></if>

then find:

$template_hook[postbit_signature_end]

above it add:

<if condition="$post[postcount] == 1"></div></if>

this should work
you can customize your options there... for the float ,margin, ad unit id or postcount

good luck