DateTimePicker - Customization Of BackColor Win7

I've created a custom DateTimePicker and implemented code I found on the web to allow customization of the BackColor of the dtp (Making use of WndProc). However, I've discovered that this doesnt work in Windows 7 with the XP Visual Styles option enabled in the project. How to make this work for Win7, without disabling the Visual Styles (the controls look ugly without them).

Below is the code I'm using:
Private _BackColorBrush As SolidBrush = New SolidBrush(SystemColors.Window)
Public Overrides Property BackColor As Color
Get
Return MyBase.BackColor
End Get
Set(value As Color)
[Code] .....