Core and Shell Building with Tenant Improvement

We have been contracted to design a core and shell building for a large office building. We applied for Core and Shell for LEED 2009. In the middle of our design process, a tenant hired us to build out the space. The tenant space includes office spaces and a large-scale data center (>1000 kW). I see two approaches to complete the energy model for the tenant improvement areas; 1) use the tenant improvement design to establish the HVAC system, lighting system, and process loads (including the >1000 data center) similar to new construction, or 2) use Table G-C and Table G-D to establish non-regulated loads and use the code-based lighting and HVAC system for both baseline and proposed models. Clearly the right approach is to switch this project from Core and Shell to New Construction. However, the tenant is not interested. Without the tenant involvement, it is unlikely that we will achieve minimum energy performance. As part the Core and Shell team, we want to certify the building. The only way to achieve the goal of the owner is to use approach 2. Comments? CURTIS CLARK PE, LEED AP BD+C SUSTAINABILITY SERVICES