The IP address on the server and or workstation is what is used to determine which site the machine is a member of based on the configuration defined in Active Directory. If it is possible for you to maintain network connectivity locally, assign an IP address from the site to the machine you are installing and it will be assigned to the corresponding site.
OR, after building the DC locally and relocating it at the remote site. Perform the following steps:
To Move a Domain Controller to Another Site
On the Programs menu, point to Administrative Tools, and then click Active Directory Sites and Services.
Expand the Sites node and the node that correlates to the site in which the domain controller resides. Expand the Servers node to display the list of domain controllers currently configured for that site.
Right-click the domain controller to be moved, and then click Move.
Select the appropriate target site, and then click OK.