Well like I said in reply to zdan's answer I found a way. Just override the OnUpdateCmdUI function in CToolBar like this
class MyToolBar : public CToolBar
{
public:
virtual void OnUpdateCmdUI(CFrameWnd* pTarget, BOOL bDisableIfNoHndler)
{ return CToolBar::OnUpdateCmdUI(pTarget, FALSE);}
}
the bDisableIfNoHndler flag is the one responsible for telling the toolbar to disable buttons if no handlers is found so I just force it to FALSE.
Though now I'm having another problem. The toolbar seem fines but it do not send the commands when I press a button. I'm not sure why because if I access the same commands from the menu it works fine. I'll try to see if this is related.
Thanks for your helps.
Update: Found my problem. Basically the problem was that my handlers to my commands were in MyFrame::PreTranslateMessage (after doing like suggested in this question's answer : http://stackoverflow.com/questions/978071/how-to-redirect-mfc-messages-to-another-object) but the commands were not sent through this function (though when accessed from the menu they did). They were sent through MyFrame::OnCommand though so I just changed the code from PreTranslateMessage to OnCommand and now everything works fine. I don't know MFC enough to know why this was the case but now everything seems to works so thanks for the help everyone.