Env: Win32 (Visual C++)

How can I implement the Mouseover event ? Assuming I have two bitmap buttons (IDC_Btn1, IDC_Btn2) in main dialog.

When Mouseover, IDC_Btn1 will change to IDC_Btn2. When Click, only the child Dialog will be displayed, and the button remains IDC_Btn2.

Any sample code, will be great. Thanks.