VC+MapX问题（如何改变TrueType字体大小，附代码）请教

CMapXStyle ftrStyle = m_ctrlMapX.GetLayers().Item("Outlets").GetStyle();       //"ftrStyle" holds the style of the feature for the       CY fontSize;   fontSize.int64=64;   ftrStyle.SetSymbolType(0);   ftrStyle.GetSymbolFont().SetName("plao1");//plao1.ttf   ftrStyle.SetSymbolCharacter(52); //Changes the symbol to a warehouse   ftrStyle.SetSymbolFontColor(255); //Changes the color of the symbol to red   ftrStyle.GetSymbolFont().SetSize(fontSize); //Changes the symbol font size

上述代码运行不正常，怎样修改TRUETYPE字体复好的大小？