Since the button is recorded as an HTMLImage, you can try getting a collection of images in the page (using DOM), traverse through the list and identify the correct image (it would help if you know the actual name of the image) and trigger a click event?
Try using SQAGetChildren and populate an array of all the objects on the screen at the time. Then traverse the array looking for the type of object you want. Continue to filter your array until you can uniquely find your object then get its index by using SQAGetProperty.
If this or any response has helped you, please reply to the thread stating that it worked so other people with a similar issue will know how you fixed your issue!