How to change the tax value( uniwell nx-5400 )

Hi guys,

I am a desperate green bean in Montreal.My register is a uniwell nx-5400.

I need to change the tax values ,but I do not have a programming manual. Before, the federal tax value is 5%, the provincial tax value is 7.5%,that is to say:if you buy sth 1$, you have to pay:1.00*1.05*1.075=1.12875. From 1st jan,2011, the the provincial tax value will be 8.5%.

I have no idea how I can deal with it , I need your help!

Thanks in advance!