In case if you want to install SEPM with latest virus definition which is used for client packages.
You may try these steps.
Open SEPM Folder from CD1 (downloaded package from file connect website)
Open the Packages folder
Rename the SAV32.dat file to SAV32.zip
Extract SAV32.zip file to SAV32 folder
Look for vdefhub.zip file
Copy the full.zip from any working SEPM which got the latest definition.
Rename it to vdefhub.zip
Replace in SAV32 folder
Rename it to sav32.dat
Follow the same procedure for SAV64.dat file
When you create the installation packages now you should have the latest definitions.