admin age available common date during email help html invoice item liked page pointers preferences signing system template testing thank-you-page thankyou time24 translated variables week working

I liked your system & am signing up this week. During testing i found that the following template variables are NOT getting translated in the thankyou page :-
[%invoice%]
[%p_date%] [%c_time24%]

These same variables are working fine on the thankyou email & other variables i tried on the thankyou age are also working fine.
Any idea why these 3 are not working? Any pointers will help.

Please make sure that you are using these variables in the "common" thank you page
(Admin > Preferences) as these are not available in the "per item" thank you page html.