Uhm… yeah, I forgot about that.
You’re using the Profile template as the detail/single entry template, right?
What you’ll have to do is follow this to create a custom version of the Profile template.
Then add the following code to the template where you want the vCard download link to show:
<?php $entry->vcard( array( 'before' => '<span>', 'after' => '</span>' ) ); ?>
My suggestion is on this line.
Hope that helps! Apologies for forgetting that that entry action would display in the sidebar too when enabled!