CEdit and text-justification

I use a multiline CEdit-Control in my dialog-based
application, and want to be able to change the text-justification via radio-buttons. The CEdit-Control comes from the dialog-ressource. I tryed the following:

I have a CEdit member variable in my dialog-class,
which is initialized in "OnInitDialog"
mEdit = (CEdit *)GetDlgItem(IDC_EDIT1);

There are 3 functions for left, center, right
that look like
void MyDlg::OnRadioRight()
{
mEdit->ModifyStyle(0, ES_RIGHT, SWP_NOSIZE);
mEdit->UpdateWindow();
mEdit->SetFocus();
}

Actually, this doesn't work.
Has anyone an idea, what's wrong.

Thanks for your help,
Lothar