If I understand your question correctly, you want to know how Project
Server knows that Resource A in Project Web Access is Resource A in a
project schedule created in Microsoft Office Project Professional?
When resources are created in Project Server, they form an Enterprise
Resource Pool. This allows Project Server to track every assignment
on every task on every project in Project Server. To find these
resources using Project Professional, connect to Project Server and
then select: Tools > Build Team from Enterprise. The Build Team from
Enterprise dialog allows you to filter resources by resource
attributes, group them, replace them, etc. The list of enterprise
resources appears on the left hand side. Resources already on the
project schedule appear on the right side. Select the enterprise
resource(s) you need and move them to the project list. They will
appear on the project schedule's Resource Sheet and you can assign
them to tasks from there.
Hope this helped,
Mark Everett PMP | MCITP
www.catapultsystems.com