If you wanna apply regular exported *.reg files use this mechanism:
[Winbatch_add_reg_32]
"%SystemRoot%\system32\reg.exe" import "%ScriptPath%\32bit_wsus_win7.reg"
[Winbatch_add_reg_64]
"%SystemRoot%\system32\reg.exe" import "%ScriptPath%\64bit_wsus_win7.reg"
Winbatch_* sections/functions allow to execute dos/windows commands.