EPM Drops + Plus Symbol from Key Values

Configuring Aastra phones (6731 and 6737) via Commercial EPM. Attempting to configure buttons to dial a code and wait for further input. For example, a directed pickup button to dial **, then wait for the target extension to be entered.

Per Aastra documentation, this can be accomplished by creating a Speeddial key and adding a plus sign at the end of the key value, like **+

A new feature for the Speeddial option allows you to configure a preset string of numbers followed by a “+”. This feature allows the phone to speeddial a prefix number and then pause to let you enter the remaining phone number. You can use this feature for numbers that contain long prefixes. For example, if you had the following Speeddial configuration in the configuration files:
{{softkey2 type: speeddial
softkey2 label: Europe Office
softkey2 value: 1234567+
softkey2 line: 2}}
after you press softkey2 on the phone, it dials the prefix number automatically and pauses for you to enter the remaining number using the keypad on the phone.

When I attempt to add the plus sign on the end of a key value in EPM, it gets dropped from the GUI, and is not written to the mac.cfg file.