Problem adding style/styleName to tableheaders of GWT CellTable colums

[Maurice Woelk]

Hi folks,
thats my first post here and i'll just use it to start with a problem i have with the GWT CellTable.

My code looks like the following:

 private void addyxzColumn() {
    // Add a text column to show the yxz.
    TextColumn<Object> txtClmn = new TextColumn<Object>() {
      @Override
      public String getValue(Object object) {
        ... // not important in this example code. Passes the specific values of the list of objects to the textcolumn.
      }
    };
    txtClmn.setCellStyleNames("columBgColor1"); // could also be done by acessing the column through the CellTable itself.
    clltblSearchResults.addColumn(txtClmn,
        SafeHtmlUtils.fromSafeConstant(AmnMessages.MSG.hjajklaskl()));
  }

I need to set the header of a specific column . Not alternating with odd and even. Just the header of this single colum. But i can't access the table header. Tried SafeHtmlHeader etc. and tried to apply the styles to these, pass them to the table via addColumn. Didn't work at all. Is there any way to achieve what i'm trying to do?
The GWT Version is 2.4.

Thanks in advance.