This map isn't a new zone. Rather, it's an additional map for the Frenzied Breach raid zone and the Spiral of Vul contested zone. To add this map to either zone, I had to play with priorities and subzones. For completeness, the full XML listing for both zones is provided. In total, Frenzied Breach has 3 sections over 3 maps. Spiral of Vul has 6 sections over 4 maps (two subzones were needed to handle overlaps).
Code:
<ImageStyle Name="exp21_dun_blackhook_raid_01_0" displayname="Blackhook Spiral: Frenzied Breach [Raid] (Fort Sunder)" zonerect="-387, -947, 590, -285" availablepriority="1">
<ImageFrame Source="images/maps/map_exp21_dun_blackhook_02.dds" SourceRect="0,0,1506,1024" />
</ImageStyle>
<ImageStyle Name="exp21_dun_blackhook_raid_01_1" displayname="Blackhook Spiral: Frenzied Breach [Raid] (Floating Steps)" zonerect="73, -636, 487, -27" availablepriority="0">
<ImageFrame Source="images/maps/map_exp21_dun_blackhook_04.dds" SourceRect="0,0,512,753" />
</ImageStyle>
<ImageStyle Name="exp21_dun_blackhook_raid_01_2" displayname="Blackhook Spiral: Frenzied Breach [Raid] (Caldera)" zonerect="-199, -200, 637, 415" availablepriority="2">
<ImageFrame Source="images/maps/map_exp21_dun_blackhook_03.dds" SourceRect="0,0,1390,1024" />
</ImageStyle>
<ImageStyle Name="exp21_dun_blackhook_contested_0" displayname="Spiral of Vul (Fort Vul)" zonerect="-387, -947, 590, -285" availablepriority="1">
<ImageFrame Source="images/maps/map_exp21_dun_blackhook_02.dds" SourceRect="0,0,1506,1024" />
</ImageStyle>
<ImageStyle Name="exp21_dun_blackhook_contested_1" displayname="Spiral of Vul (Sullen Sanctuary)" zonerect="-660, -413, 13, 515" availablepriority="4">
<ImageFrame Source="images/maps/map_exp21_dun_blackhook_01.dds" SourceRect="0,0,1024,1411" />
</ImageStyle>
<ImageStyle Name="exp21_dun_blackhook_contested_2" displayname="Spiral of Vul (Sullen Sanctuary)" zonerect="-660, -413, 13, 515" availablepriority="2" availablerect="-199, 270, 13, 415">
<ImageFrame Source="images/maps/map_exp21_dun_blackhook_01.dds" SourceRect="0,0,1024,1411" />
</ImageStyle>
<ImageStyle Name="exp21_dun_blackhook_contested_3" displayname="Spiral of Vul (Vuldor)" zonerect="-199, -200, 637, 415" availablepriority="3">
<ImageFrame Source="images/maps/map_exp21_dun_blackhook_03.dds" SourceRect="0,0,1390,1024" />
</ImageStyle>
<ImageStyle Name="exp21_dun_blackhook_contested_4" displayname="Spiral of Vul (Vuldor)" zonerect="-199, -200, 637, 415" availablepriority="-1" availablerect="73, -200, 111, -27">
<ImageFrame Source="images/maps/map_exp21_dun_blackhook_03.dds" SourceRect="0,0,1390,1024" />
</ImageStyle>
<ImageStyle Name="exp21_dun_blackhook_contested_5" displayname="Spiral of Vul (Floating Steps)" zonerect="73, -636, 487, -27" availablepriority="0">
<ImageFrame Source="images/maps/map_exp21_dun_blackhook_04.dds" SourceRect="0,0,512,753" />
</ImageStyle>