validate url in vb.net but let few characters pass through

Question

i have this regulareexpressionvalidator on the URL textbox with ValidationExpression="http://([\w-]+.)+[\w-]+(/[\w- ./?%&=]*)?". Now the problem is that the websites that the users are going to input are like the following - http://www.fed.com/name={name}

The problem with this validator is that the "{" and "}" are not being passed through. How do i make the validation with the exception of "{}" ?