How to control Captivate 8 button from external Flash movie?

I have embedded a flash animation into a captivate 8 slide. In the captivate slide there are two Next buttons (not the Captivate navigation) - a Next image and underneath a Next button. From the embedded flash file I want to hide the Next image so that the underneath Next button can be clickable to move to the next slide. How can I do this from the embedded Flash file? Also I already have few Advanced actions written in Captivate. How the corresponding user defined variables and these advanced actions be called/controlled from embedded Flash?

Any help will be much appreciated. Thanks.