umbraco: get USER properties, NOT member properties in XSLT

Here's my scenario:

1. Added an Author Picker to the default umbBlogPost (from the blog4umbraco package) which gives me access to the author's id in an XSLT macro
2. The Author Picker is pulling up a list of umbraco users, not members
3. I want to the display the author's username in xslt output

I've tried several different ways based on Google searches which all seem to be using the Membership API, such as umbraco.libary:GetMember and umbraco.library:GetMemberName which is not working, again, as I am dealing with umbraco users, not members. There doesn't appear to be any user equivalent methods, i.e., umbraco.libary:GetUser or umbraco.library:GetUserName.

Does anyone know how I can get user properties in an xslt macro? I am using version 4.7.2. Also, while I'm currently working with xslt, if this can be done with a Razor macro (if supported in 4.7.2?) I am open to seeing this approach as well. Thanks.

I ended up solving this by writing a Razor macro. The key was to add @using umbraco.BusinessLogic; at the beginning of the macro. This namespace provides the API required to get user data as opposed to member data.

For anyone interested, here's the macro I wrote:

@using umbraco.BusinessLogic;
@inherits umbraco.MacroEngines.DynamicNodeContext


<div>
  <h1>
    From Our Blog
  </h1>
  <ul>
  @foreach(var i in @Model.AncestorOrSelf("umbHomepage").Descendants("umbBlogPost").OrderBy("PostDate desc").Take(5))
  {
    <li>
      <p>
        <a href="@i.NiceUrl" title="@i.Name">@i.Name</a><br />
        by <a href="#">@umbraco.BusinessLogic.User.GetUser(Int32.Parse(i.blogAuthor)).Name</a> on @i.PostDate.ToString("MMM dd, yyyy")
      </p>
    </li>
  }
  </ul>
</div>