How to assess if Cancel was clicked or coor was chosen?

Continuing from my previous question

http://social.msdn.microsoft.com/Forums/en-US/iewebdevelopment/thread/34f232a1-f9b7-4e34-a872-2237917be87e

Where I took the advice to use the ChooseColorDlg popup.

And with reference to this page

http://msdn.microsoft.com/en-us/library/ie/ms536349(v=vs.85).aspx

And these comments (lower down on above linked page)

Cancel button
If the user chooses Cancel, the initial colour passed to the dialog is returned. If no initial colour is passed to the dialog and the user chooses cancel, 0 is returned. There is no way of knowing if the user chose black, or cancel. In most cases this is not a problem, but if no initial colour was passed to the dialog, because the current colour is transparent (for a background), then if the user selects cancel it is not possible to determine if the action should be "Don't change the colour from transparent", or "change the colour to black". Care needs to be taken in this circumstance.

I have now arrived at a situation whereby I cannot tell if the user clicked on cancel or chose black, How would I address this issue?

DocZaf