Adding CUSTOM images to command bar button

i'm trying to add CUSTOM images to command bar buttons in office XP by add in, in vba i can do this:

Dim picPicture As IPictureDisp
Dim picMask As IPictureDisp

Set picPicture = stdole.StdFunctions.LoadPicture("c:\spo.bmp")
Set picMask = stdole.StdFunctions.LoadPicture("c:\spm.bmp")

myButton.Picture = picPicture
myButton.Mask = picMask

adding stdole class to vb.net let me create IPictureDisp but i doesnt have LoadPicture method.
Any idea how it can be done?
thanks