How to set toolbar' button caption is left aligne

How to set toolbar' any button  caption is left aligned and font style, and disviable any btn's tooltip.  thks

thk for your response. but it's not,  my code is:
int CMainFrame::OnCreateControl(LPCREATECONTROLSTRUCT lpCreateControl)
{
        CXTPControlButton* pButton = (CXTPControlButton*)CXTPControlButton::CreateObject();
        lpCreateControl->pControl = pButton;
        pButton->SetID(lpCreateControl->nID);
        pButton->SetIconId(ID_TOOLBAR_BTN_TEST_STR);
        pButton->SetStyle(xtpButtonCaption);
        pButton->SetFlags(pButton->GetFlags() | xtpFlagControlStretched );
        pButton->SetPrompt("TestString");
}

But "TestString" is center aligned, no left aligned

isee, but i don't want have icon.