Can't get [pm_user] shortcode working from within a template


I'm trying to manually insert the send private message button in the bbPress templates. I know this can be achieved automatically via hooks but I'm opting to do it manually because I'd like to control some of the properties of the button.

Here's my code within loop-single-reply.php but nothing is showing.

<?php echo do_shortcode( '[pm_user user_id="2" in_the_loop="0" text="Send PM"]' ); ?>

When debugging, I swapped the shortcode for the message inbox and this worked perfectly so I'm guessing the pm_user shortcode might still need a little work?

There are a few reasons why I am opting for the manual integration instead of the automatic Add-on bbPress integration:

1. My bbPress theme design uses bbPress actions and hooks on various places on the page (different from the norm). This causes the Send Message button to appear in two places and I only need it to appear once. See example here:
I'm not going to remove the second do_action from my template as I plan to use it later.

2. I need to be able to change the text from Message Me to another string. The shortcode apparently allows this.

Hope you can help,