You have to open the objectcreationlist.inc. There is the "ObjectCreationList OCL_SpawnSummonRogash" ,where you change the Count of the Troll and where you can delete the summon of Rogash.
For Building Rogash, you have to open the playertemplate.ini and then you have to add Rogash in the "BuildableHeroesMP" of Faction Angmar at the last place. Afterthat you have to change the commandset of the building, where you want to build him.
For example the normal Angmarbarrackscommandset:
CommandSet AngmarBarracksCommandSet_Edikt
 InitialVisible = 8
      1 = Command_SelectRevivablesAngmarBarracks
      2 = Command_ConstructAngmarDarkDunedainHorde_Edikt
      3 = Command_ConstructAngmarDunedainPikemanHorde_Edikt
      4 = Command_ConstructAngmarDarkRangerHorde_Edikt
      5 = Command_ConstructAngmarNumEliteHorde
      6 = Command_Sell 
      7 = Command_ConstructAngmarSchwarzeRitterHorde
      8 = Command_PurchaseUpgradeGemächerderSchwarzenGarde
      9    = Command_FakeRingHeroReviveSlot
      10   = Command_FakeCreateAHeroReviveSlot  
      11   = Command_FakeHeroReviveSlot1
      12   = Command_DurmarthReviveSlot
      13   = Command_FakeHeroReviveSlot3
      14   = Command_GenericReviveSlot4
      15   = Command_FakeHeroReviveSlot5
      16   = Command_FakeHeroReviveSlot6
      17   = Command_FakeHeroReviveSlot7
      18   = Command_FakeHeroReviveSlot8
      19   = Command_RadialBack
Endand the changed Commandset
CommandSet AngmarBarracksCommandSet_Edikt
 InitialVisible = 8
      1 = Command_SelectRevivablesAngmarBarracks
      2 = Command_ConstructAngmarDarkDunedainHorde_Edikt
      3 = Command_ConstructAngmarDunedainPikemanHorde_Edikt
      4 = Command_ConstructAngmarDarkRangerHorde_Edikt
      5 = Command_ConstructAngmarNumEliteHorde
      6 = Command_Sell 
      7 = Command_ConstructAngmarSchwarzeRitterHorde
      8 = Command_PurchaseUpgradeGemächerderSchwarzenGarde
      9    = Command_FakeRingHeroReviveSlot
      10   = Command_FakeCreateAHeroReviveSlot  
      11   = Command_FakeHeroReviveSlot1
      12   = Command_DurmarthReviveSlot
      13   = Command_FakeHeroReviveSlot3
      14   = Command_GenericReviveSlot4
      15   = Command_FakeHeroReviveSlot5
      16   = Command_FakeHeroReviveSlot6
      17   = Command_FakeHeroReviveSlot7
      18   = Command_FakeHeroReviveSlot8
      19   = Command_GenericReviveSlot9
      20   = Command_RadialBack
EndYou have to change the commandrangecount, too, of the CommandButton Command_SelectRevivables AngmarBarracks from 11 to 12.
CommandButton Command_SelectRevivablesAngmarBarracks
    Command                 = PUSH_VISIBLE_COMMAND_RANGE
    TextLabel               = CONTROLBAR:SelectRevivablesMenFortress
    ButtonImage             = UCCommon_EvilHeroes
    ButtonBorderType        = SYSTEM
    DescriptLabel           = CONTROLBAR:ToolTipCommandSelectRevivablesAngmarBarracks
    Radial                  = Yes
    CommandRangeStart        = 8
    CommandRangeCount        = 12
End