Unications can do 5 tone, I think your trying to enter the cap code in the wrong spot.
There's several variations of 5 tone signalling, the various standard formats are identified with names like CCIR, ZVEI, EIA or EEA and there's some non-standard versions in use as well. You have to know which 5 tone format the Icom is using to program the Unication.
The 5 tone format in Unication PPS is set up in the Protocol Parameter Setting tab, either pick one of the standard formats in the 'Tone Table' pull down or the 'User Define' if you need to customize the tone table.
The 5 tone cap code, 77777 in your case, is entered in the Group ID Setting tab. The actual tone frequencies are pulled from the tone table set earlier: