Her contract + visa are the best evidence to prove her working in Hong Kong, whats more, i dont understand why her still need a scholarship, as the $ she earn in hk already more than those local people in their country.
It's understandable for an employee to look for a better job, and if someday my maid wants to leave, i will write her a nice reference letter (provided that she has very good performance), as long as she tells me the truth, definitely wont help her if she lies to me.
Why dont you ask her and be honest? If she refuses to tell you the truth, you have the right for not doing her the favour.