title: Checked binding using an object property in knockout js
body: <p>[My first attempt at describing the issue was clear as mud; I significantly reworked it in the name of clarity. I hope I haven't failed miserably...again.]</p>
  
  <p>I'm attempting to set up a master/details view using knockout where the details pane includes a list of checkboxes. I have an array of User objects, each of which has in turn an array of UserPermission objects where the PermissionId property is what should determine if the checkbox is checked. </p>
  
  <p>So, in short: There's a master list of users, from which you select one to view details. In the details pane, I have a list of checkboxes (generated from a list of available permissions). Whether or not a given checkbox is checked should be determined by the persences of a matching PermissionId within the array of UserPermission objects associated with the current user.</p>
  
  <p>My question is - how do I get the checkboxes to use the user.UserPermissions.PermissionId for the checked binding? </p>
  
  <p>Here's a jsfiddle of <a href="http://jsfiddle.net/szcp2/3/" rel="nofollow">my attempt thus far</a>, and here's <a href="http://jsfiddle.net/R87Cg/2/" rel="nofollow">another approach I've tried</a>.</p>