How to get active directory userid from a string field of a work item

By synchronizing a project plan from a MS Project .mpp to TFS, I want to sync a field that is a string representing the name of the project manager affected to a project. As a rule, this string is taken from Active Directory's valid users group in TFS.

I am searching for a way to obtain the userid as well in order to query a SQL Server DB. Is there a was to get the userid from AD when you have the user's name? This seems to be an option, whereas not the best.

If there would be a way to capture the userid in this field as well at the same time that i sync the project manager's full name, this would be the best alternative. Any suggestions?

<FIELD name="Project Manager" refname="Custom.ProjectManager" type="String" reportable="dimension">
<HELPTEXT>The name of the project manager.</HELPTEXT>
<SUGGESTEDVALUES expanditems="true" filteritems="excludegroups">
  <LISTITEM value="[global]\Project Collection Valid Users" />
</SUGGESTEDVALUES>
</FIELD>

Solution

This is a workaround I tought of. The downside is that the USERID is shown whenever you see the name of the project manager.

Work item type XML file

    <FIELD name="Project Manager" refname="Custom.ProjectManager" type="String" reportable="dimension">
    <HELPTEXT>The name of the project manager.</HELPTEXT>
    <SUGGESTEDVALUES expanditems="true" filteritems="excludegroups">
      <LISTITEM value="(ID='DOEJ24') John Doe " />
      <LISTITEM value="(ID='DOEJ23') Jane Doe " />
      <LISTITEM value="(ID='SMIJ03') John Smith " />
      <LISTITEM value="(ID='COSG01') George Constanza " />
      <LISTITEM value="(ID='BRAT99') Tom Brady " />
    </SUGGESTEDVALUES>
    </FIELD>

    var projectManager = WorkItemStore.GetWorkItem(Convert.ToInt32(id))["Project Manager"]);
    var pmUserId = projectManager.SubString(5, 6);

This way I can easily query my database which has the project manager user id column.