Hardcode ad spots into theme

Hello,
I am looking for a way to hardcode adspots into my theme useing the ad injection plugin and the “Alt Ad Spots”.
I was thinking of something like this:

<?php if (( function_exists('adinj_print_ad')) && (adinj_print_ad('ad_bottom_alt_1') =''){ ?>
	<?php { adinj_print_ad('ad_bottom_alt_1'); } ?>
<?php } else { ?>
	<?php if ( function_exists('adinj_print_ad')) && (adinj_print_ad('ad_bottom_alt_2') =''){ ?>
		<?php { adinj_print_ad('ad_bottom_alt_2'); } ?>
	<?php } ?>
<?php } ?>

I cant figure out how to check if the code was inserted into the “Alt Ad Code box” or if its empty.
Maybe there is an easier way I didnt find?

Any help is appreciated.
Regards
Meags

http://ww.wp.xz.cn/extend/plugins/ad-injection/