Connection Poll Helper error

[cosmoKenney]

I'm getting a null return from this line:
PropertyInfo connectionPoolIdentityConnectionStringPropertyInfo = connectionPoolGroupIdentityType.GetProperty( "ConnectionString", privateInstance );

I'm on .net 4, asp.net app.
I've tried to enumerate the properties (connectionPoolGroupIdentityType.GetProperties) and only get a couple of oddly named properties out of it. Any clues to get this working?