Check out the form 61s ... or whatever the hell they're called now that the Bay Street Brain Trust has taken over ... here's a quick way into sedar, click the letter with which the name of company begins - http://www.sedar.com/issuers/issuers_en.htm
... they always have management holdings i think, like the annual reports do .... then if it's a BC-registered company [which National isn't, it was an Alberta jcp to start], you'll find a lot on it here - http://www.bcsc.bc.ca/ .... that's the whole BCSC site, can't find my direct link ... but there's a lot on the site, including itemised insider trades and holdings etc ...... cheers