It appears that Joint Assault Signal Companies (JASCOs) were not just army but grouped tri-service radio specialist who were used to co-ordinate army, navy and air force combat units, especially air and artillery support, in both the Pacific & European theatres and came under the Signal Corps. Source http://signal.army.mil/history/history-JASCO.html
There was a detachment of the 592nd JASCO with each of the 81st Division’s infantry regiments (321, 322 and 323) during the attack on Peleliu during 1944 but I don’t now if they were with the 81st Division throughout the Pacific campaign.
It may be useful to contact the creator of the 295th JASCO’s web site at http://jasco295.tripod.com/
as I’m sure he will have seen some references during his search of the documents he mentions.
Failing that contact the Signal Corps museum at Fort Gordon GA.