Partway there.  Un-checking the "Show strings in indexes" option solved the display problem.  I'm still faced with the inability to enter the IP Address in Unbrowse's index builder.
Note that the index builder's Type Info column describes the field as "IpAddress,OctetString,Fixed Size: 4" and that entering the value "
192.168.0.1" yields the index ".49.57.50.46.49.54.56.
46.48.46.49" (characters turned to bytes).
--===========================================================================
-- Trap Destination Table
--===========================================================================
alarmTrapDestTable OBJECT-TYPE
SYNTAX		SEQUENCE OF AlarmTrapDestEntry
MAX-ACCESS	not-accessible
STATUS		current
DESCRIPTION	"Alarm Trap Destination Table Object"
::= { hcuAlarm 7 }
alarmTrapDestEntry  OBJECT-TYPE
SYNTAX		AlarmTrapDestEntry
MAX-ACCESS	not-accessible
STATUS		current
DESCRIPTION	"Alarm Trap Destination Entry Object"
INDEX       { destinationIpAddress }
::= {alarmTrapDestTable 1}
AlarmTrapDestEntry ::=
SEQUENCE {
destinationIpAddress	IpAddress,
status					RowStatus
}
destinationIpAddress OBJECT-TYPE
SYNTAX		IpAddress
MAX-ACCESS	read-create
STATUS		current
DESCRIPTION	"ip address for a trap destination"
::= {alarmTrapDestEntry 1 }
status OBJECT-TYPE
SYNTAX		RowStatus
MAX-ACCESS	read-create
STATUS		current
DESCRIPTION	"status column for row creation purpose"
::= {alarmTrapDestEntry 2 }
Thanks!