To refresh explorer for using the icon and typename you need to use this api:
Code:
'In declarations
Declare Function SHChangeNotify Lib "shell32.dll" (ByVal wEventID As Long, ByVal uFlags As Long, ByVal dwItem1 As String, ByVal dwItem2 As String) As Long
'After associating
 SHChangeNotify &H8000000, 0, vbNullString, vbNullString