Create a custom PrincipalPermission for ASP.Net
<p>I have to build a web application with form authentications and I have my own roles and permissions for each user (Add, Update, Delete, View). PrincipalPermission is very useful in denying any user without permissions to from running a specific method, but I don't want to use a membership — I have my own permissions and roles.</p>

<p>How I can create my own PrincipalPermission to check my custom privileges? I think it must be like this <code>[CustomPrincipalPermission(SecurityAction.Demand,UserPrivilege=currentUser.x)]</code>
Where <code>currentUser.x</code> is bool to indicate if user have to access this method.</p>

<p>Is this possible, and if so how?</p>
