Processing the OK button in a property sheet

Question

I am using Win32 native code
So I create a property sheet using the PropertySheet macro IT has three pages ( all created using CreatePropertySheetPage)
So when the user presses ok how do I go about collecting data from each page. I get a message PSBTN_OK in the propsheet callback but how do I get the HWND of each individual page so taht I can call GetText or getting the buttons checked state etc.
I guess my question is what is the correct way to clean up when a user select ok or cancel on a property sheet