How to get an invitation letter for first time travellers to China for business purpose?

Our marketing officer is a first time traveller to CHINA, he is to go with our two directors as the job of
international trade has thus been delegated to him.
What should he do to get an authorise letter of invitation from chinesse governent as we were told that
there is no room for a first time travellers. And i believe his own case is different , he was INDIA just last year, and i do not get the reason why he could not be allowed to travel.
I want to know what we should do for his case.