More about Tab Controls

I have a Tab Control. All the pages of the Tab Control display the same buttons and fields. My idea was:
OK, it's easy: I don't have to hide anything. I just make a TRANSPARENT tabcontrol. Then I add all my controls, which will be always visible, since they don't have to change.
So, the controls don't have to change, but the content will be changing according to the selected tab. That's easy, I only have to use an if-sentence and the .GetCurSel() method.
Something like:
          if (m_CTab.GetCurSel()=3)
             {m_NameInput="three"}

(All that within the OnSelchangeTab method).
OK, it works fine. Now comes the problem:
One of the fields is a text-input field, with the following code:

void CFhgDlg::OnChangeNameInput()
{
        UpdateData(TRUE);
        TC_ITEM tcItem;
        int tab = m_CTab.GetCurSel();
        if (tab >= 0)
        {
            PSTR text=(PSTR)(LPCTSTR)m_Name;
            TC_ITEM tcItem;
            ::ZeroMemory((PVOID)&tcItem, sizeof(tcItem));
            tcItem.mask = TCIF_TEXT;
            tcItem.pszText=text;
            m_CTab.SetItem(tab,&tcItem);
            UpdateData(TRUE);
         }

This code comes from a last week question: it just changes the name of the tab, displaying what the user is typing in the text-input field.
That works, the name of the tab is changed, but all the controls in the
tabcontrol dissapear (with the m_CTab.SetItem(tab,&tcItem) command). The tab-control is no longer transparent!! What can I do??
And something more:
How does the property "transparent" of the tab-control work?(in the ressource editor: right click on a tab-control -> Properties -> Extended Styles -> Transparent). I mean, when I mark this property, the tabcontrol isn't transparent at all. I have to left it unmarked if I want to use it as transparent.