I've been checking this and found out something... that locId is in fact the id of the system message you get when typing /loc in chat.
I've used this, which is near conquest messages:
@ClientString(id = 5225, message = "Current location: $s1 / $s2 / $s3 (near the base)")
and seems fine, but I did not find out where that bbs value is taken from.
Index: dist/game/data/mapregion/conquest_fire_area.xml
===================================================================
--- dist/game/data/mapregion/conquest_fire_area.xml (nonexistent)
+++ dist/game/data/mapregion/conquest_fire_area.xml (working copy)
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<list enabled="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../xsd/MapRegion.xsd">
+ <region name="conquest_fire_area" town="Kellond's Secret Barracks" castle="0" locId="5225" bbs="30">
+ <respawnPoint X="20830" Y="-225445" Z="-3789" />
+ <respawnPoint X="20830" Y="-225445" Z="-3789" isChaotic="true" />
+ <map X="20" Y="11" />
+ </region>
+</list>
\ No newline at end of file
Index: dist/game/data/mapregion/conquest_water_area.xml
===================================================================
--- dist/game/data/mapregion/conquest_water_area.xml (nonexistent)
+++ dist/game/data/mapregion/conquest_water_area.xml (working copy)
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<list enabled="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../xsd/MapRegion.xsd">
+ <region name="conquest_water_area" town="ConquestTown" castle="0" locId="5225" bbs="30">
+ <respawnPoint X="-16330" Y="-189326" Z="-4005" />
+ <respawnPoint X="-16330" Y="-189326" Z="-4005" isChaotic="true" />
+ <map X="19" Y="11" />
+ <map X="19" Y="12" />
+ </region>
+</list>
\ No newline at end of file