How to switch off validation summary HeaderText for a perticular CustomValidator

I have 6 required field validators and 1 custom validator. ErrorMsg is common for required fields so I have set that msg to validation summery headertext but the problem is that error message is coming with custom validator too. In case of custom validator I want only customValidator error messsage not Header开发者_如何学Go text. How can I do that> Do I have to add new validation summer for custom validator with no header text OR there is any smart solution?

document.getElementById('<%= vsPlaceOrder.ClientID %>').headertext = "";