If this is the case for your organization and the Locally Deployed SELECTserver is only accessible on the LAN (an intranet site), then it will not allow your users to access via WAN.
The best solution would be to move the assets to SELECTserver Online (a Bentley Hosted Server).
This would allow both internal and external users access to the organization's available license(s) via a simple, yet secure, connection to the web.
For further details on moving your assets to SELECTserver Online contact either your Account Manager or a Bentley Product Activation Specialist.
For more details on the technical requirements of both SELECTserver Online and the Locally Deployed SELECTserver, Click Here
TSQ