The following code will convert a decimal number into a 8 bit binary. If you want to convert bigger numbers simply change the loop counter to the number of bits you want - 1.

Code:
    Dim iNum As Integer
    Dim iPos As Integer
    Dim s As String
    
    iNum = 28
    For iPos = 0 To 7
      If (iNum And (2 ^ iPos)) Then
        s = "1" & s
      Else
        s = "0" & s
      End If
    Next iPos
    
    MsgBox s