The Mk3A SeaKing with the MSS (multi sensor system) turret fitted can carry out auto letdowns to a radar designated target (in fact so can the Mk3) but the Mk 3 requires the radar operator to talk the pilot to the letdown position before the trans down is initiated.
The rad op in a 3A can transmit the target lat/long to the Rnav and the co pilot can use the Rnav and SN500 to let down to the target - in IMC/icing if required.
If we are using the FLIR to locate a target, then the Radop can talk the aircraft to the overhead where the position is entered into the Rnav and either overfly or Rnav teardrop to the hover, again usin Rnav/SN500.
The value of being able to letdown to a FLIR designated target is limited since the FLIR will be useless IMC and visual procedures as described above can be used otherwise.
One of the best features of the 3A is that there is a hover button that selects a doppler hover when you are less than 20 kts doppler and within 20 feet of the set hover height in the SN500.
What has been described as the capability of the S92 is what is required to do the SAR job properly but it still won't have an NVG capability.