add: a problem when using "SendMessage" to retrieve the number of the buttons on toolbar

when retrieving the caption of command button on the toolbar ,the ID of button
must be set to wParam parameter of API "sendmessage",
ie . wParam =idbutton, according to SDK document.
how can i get the IDbutton if i add two button on toolbar by its property
dialog box?
IDbutton = what???????????
##############################################################
Str=Space$(256)
throw = SendMessage(GetWindow(Toolbar1.hwnd, GW_CHILD),_ TB_GETBUTTONTEXTW,IDbutton,Str)
##############################################################