Here is some information about other radios I know.    Maybe you can use this for APRS, maybe for other applications. 

IC-H16 & U16

From Eric VK2KUR:

Instructions for Programming the ICOM IC-H16 & U16

Program Mode

Press & hold FUNC and enter 1, 5, 9, 3, 5, 7. Two dots (:) show between "CH" and channel number e.g. CH:12.

Frequency

Hold FUNC, press 5, displays frequency. Whilst still holding FUNC enter new frequency in full e.g. 1, 4, 7, 0, 2, 5 and then press ENT. Display reverts to channel number.

Offset

Hold FUNC, press 4, displays offset. Whilst still holding FUNC press q for - or p for + and then the offset e.g. 0, 0, 6, 0, 0 for 600kHz or 0, 1, 5, 0, 0 for 1.5mHz etc. Press ENT.

ENCODE TONE

Hold FUNC, press 1, displays tone number. Whilst still holding FUNC press new tone number (1 to 38), then ENT.

DECODE TONE

Hold FUNC, press 2, displays tone number. Whilst still holding FUNC press new tone number (1 to 38), then ENT.

CANCELLING ALL TONES

Hold FUNC, press 1 or 2 then CLR then ENT.

UNPROGRAMMED CHANNELS

To access un-programmed channels key in channel number followed by ENT.

EXIT PROGRAMMING MODE

Hold FUNC, press CLR

From: Steve Powell <steve.powell@channel-two.demon.co.uk>

Hi, additional IC-H/U16 programming functions using the same method as those listed by Eric ...

CUSTOM CHANNEL NUMBER Hold FUNC, press 7. Whilst still holding FUNC enter a 2 digit number from 17 to 99 or 00 to assign a custom number to that channel. Note that you cannot assign 01 to 16 as they already exist as the 'real' channel numbers.

TRANSMIT INHIBIT (on a per channel basis) Hold FUNC, press 9. This inhibits transmit for the selected channel. Repeat the operation to enable transmit again. Note that the radio gives no indication whether transmit is inhibited or not until you actually try to tx.

Here's a link to a manual that might help you.