title: IdentityServer3 - Add token inside token for custom grant type (act-as schema)
body: <p>I need to add a token inside a token for an "act-as" schema on a custom grant type in IdentityServer3.
  I tried with <code>PreserveAccessToken</code> but it just adds the token as a claim in the current ClaimsPrincipal, but can't find a way to nesting it as a claim when getting another token to pass along to the next service/api in the chain.</p>
  
  <p>The idea behind this is for being able to keep an audit of all the hops from the end-user to the last service/api in a chain  of calls.</p>