I've been looking all over the Internet tonight to try to confirm this but have only found a draft of AC 91.207-a to support my belief.
I believe that an ELT certified under TSO 91a requires that the remote panel be installed unless the ELT is visible and accessable by the pilot.
I am including a link to a draft of the AC and an excerpt from that document.
The installation manual for the AK-450 also indicates that the remote panel is not an aoptio and must be installed.
http://www.ihsaviation.com/ac/ac91207-1.pdf
5. CHARACTERISTICS OF NEW TSO’S. TSO-C91a provides for better G-switch activation,
a requirement for a defined carrier frequency for Search and Rescue Satellite-Aided Tracking
(SARSAT), cockpit monitor light and activation switch, more stringent environmental standards,
and improved installation and inspection instructions. TSO-C126 ELT’s provide for global
coverage, personal identifier, greater accuracy, and instant Search and Rescue (SAR). At this
time, the FAA recommends, but does not require carriage of the 406 ELT’s that would provide a
definite enhancement over the minimum requirements of the regulations.
NOTE: TSO-C91 ELTs units are no longer manufactured as of January 21,
1995.
6. ACTIVATION MONITOR (TSO-C91A). (Not Applicable to Survival ELT). An aural and/or visual monitor (integral or remote from the ELT unit) shall be provided to alert the pilot
when the ELT has been activated and is transmitting. ELT remote controls shall be provided, if
the ELT local controls are not assessable from the pilot’s position. The following are additional
monitor requirements:
a. Aural Monitor. If not integral to an ELT, an aural monitor shall be installed in the aircraft.
The monitor shall provide a distinct signal with a minimum intensity level of 90 dBa measured
one meter (3 feet) from the source.
b. Visual Monitor. The visual monitor shall be designed for viewing from the pilot’s position.
The monitor shall be visible under normal daytime ambient light conditions at one meter (3 ft.).
c. Remote Control. Remote controls shall provide the MANUAL ON, ARMED and RESET
modes. The OFF mode shall not be available.
You might want to confirm whether it is legal to install an ELT cerified under TSO C91a without the remote. I will try to see if I can find additional information when I can get my installation manual in my hands.