VS 2010 Text Rich Text Box not showing when saving panel content as Image

Hello,

Currently, I am using the code below to save the contents on a panel as an image. The thing is, all contents except for the text in the rich textbox is being saved. Can anyone help me out?

Declare Auto Function SendMessage Lib "user32" ( _
ByVal hWnd As IntPtr, _
ByVal Msg As Integer, _
ByVal wParam As IntPtr, _
ByVal lParam As Integer) As Integer
Private Enum EDrawingOptions As Integer
PRF_CHECKVISIBLE = &H1
PRF_NONCLIENT = &H2
PRF_CLIENT = &H4
PRF_ERASEBKGND = &H8
PRF_CHILDREN = &H10
PRF_OWNED = &H20
End Enum

Private Function PrintPanel()
Const WM_PRINT As Integer = &H317

Dim myBmp As Bitmap
Dim myGraphics As Graphics
Dim hdc As System.IntPtr

myBmp = New Bitmap( _
Me.pnlContent.DisplayRectangle.Width + pnlContent.Padding.Left + pnlContent.Padding.Right, _
Me.pnlContent.DisplayRectangle.Height + pnlContent.Padding.Top + pnlContent.Padding.Bottom)

myGraphics = Graphics.FromImage(myBmp)
myGraphics.DrawRectangle(Pens.White, New Rectangle(0, 0,
Me.pnlContent.DisplayRectangle.Width + pnlContent.Padding.Left + pnlContent.Padding.Right * 2, Me.pnlContent.DisplayRectangle.Height + pnlContent.Padding.Top + pnlContent.Padding.Bottom * 2))
hdc = myGraphics.GetHdc
'"FormsDispPanel" is your PAnel to print
Call SendMessage(pnlContent.Handle, WM_PRINT, hdc, _
EDrawingOptions.PRF_CHILDREN Or _
EDrawingOptions.PRF_CLIENT Or _
EDrawingOptions.PRF_NONCLIENT Or _
EDrawingOptions.PRF_OWNED)

myGraphics.ReleaseHdc(hdc)

myBmp.Save(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\out.png")

myGraphics.Dispose()
myGraphics = Nothing

myBmp = Nothing

Return True
End Function

Friend WithEvents prntDoc As New PrintDocument()

Private Sub prntDoc_PrintPage(ByVal sender As Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs) Handles prntDoc.PrintPage
e.Graphics.DrawImage(Me.PictureBox1.Image, 0, 0)
End Sub

Thanks in Advance!