So I'm not an advanced lock picker but I've been interested in the hobby and have a tubular lock impressioning tool (KLOM) which I used to open the key lock. This is all good but the safe doesn't open even when the key has been turned. The actually key tube pops forward out of the safe front and you can press it back into the safe. What does this mean? Does the combination have to be known as well?
I called up Sentry and they basically told me that I wasn't allowed to open it and I should consult a locksmith. I told them I am a hobbyist (and that we owned the safe, etc) and had the key opened up and wondered why the safe wasn't opening. At this point she basically took me as a thief and told me there was nothing she could do and they had no information or guides on such an old safe

So what do I do? Am I screwed? I just want some sort of documentation to make things clear on how this thing is opened...
I can't find ANY info on this safe online or anywhere - here's the only real info I could find and I called them and they don't know anything or have one :/ http://www.4keyslocksafes.com/sentrypage.htm
Thanks for any help you guys can give - I'd hate to have to end up drilling this thing but I suppose if that's what has to be done...