Increment automatically a number in text field



Hi all,

I'm newbie on LiveCycle Designer 8. I created a form with different field. Everything is working fine but I would like to automatically increment a number contained in textfield. for example, the default value is: RMA0001,

I would like, increase the last number each time that I click on special button. I visited the following topic, but sorry I don't understand:

Could you help please?

Let me know