Cannot call back missed calls containing the plus symbol

On the M10KLE handsets, missed calls are shown as a string with "+XX" at the start, where XX represents the country code of the number.

Trying to call back this number is impossible, as the handset says "number with symbols or alphabets is not dialable". Instead we have to manually write in the number without the leading +XX (if it is a national number), or alternatively write 00XX in front.

How can we solve this? Is there a dial plan rule we can put into the M100 base station config?