Filter Module output

i just finish the module tutorial and i have few questions

i've installed gmap module that allow me to insert macros to block and display the map
i want to make another module that generate the macros from my database

so i wrote the following code.

<?php
/**
* Valid permissions for this module
*/
function gmap_dynamic_perm() {
return array('access gmap_dynamic_perm content');
}

function gmap_dynamic_block($op = 'list' , $delta=0,$edit = array()){
if ($op == "list") {
// Generate listing of blocks from this module, for the admin/block page
$block = array();
$block[0]["info"] = t('gmap dynamic');
return $block;
} else if ($op =='view'){

$form['block_settings']['body_field']['format']['#collapsible']=0;
$block['subject'] = 'On This Date';
$block['content'] = "[gmap markers=small lgray::30.886197750791244,121.13525390625 |zoom=6 |center=30.41078179084589,120.25634765625 |width=300px |height=200px |control=Small |type=Satellite]";
return $block;
}
}

but the result is just printed on the screen rather than filter it to gmap.

Thank you .