[Andreas]

Hmm, we use a very custom style that has almost nothing in common with the default style ^.^
Lemme check ...

In Template pm_newpm FIND and REMOVE

else if (formname.dopreview != true)
{
<if condition="$show['trackpm']">
        if (confirm("$vbphrase[request_receipt_for_message]"))
        {
                formname.receipt.value = 1;
        }
</if>
}

FIND and REMOVE

<input type="hidden" name="receipt" value="0" />

FIND

<div><label for="cb_parseurl"><input type="checkbox" name="parseurl" tabindex="1" $checked[parseurl] />$vbphrase[automatically_parse_links_in_text]</label></div>

BELOW that ADD

<if condition="$show[trackpm]">
<div><label for="cb_receipt"><input type="checkbox" name="receipt" value="1" id="cb_receipt" tabindex="1" <if condition="$bbuserinfo[fieldx]">checked="checked"</if> />$vbphrase[request_receipt_for_message]</div>
</if>

Where fieldx is the custom profile field for setting the default.