We have predefined custom fields, some of which allow multiple values. I need to be able to set multiple values on custom fields when I am creating (or modifying) projects/folders with the API. The documentation indicates that custom field values must be strings (not arrays of strings as one might expect for being able to specify multiple values).
I have tried the following three experiments:
1. Using an array of strings in spite of what the documentation says. This results in a "bad request" error.
2. Adding multiple values in the same string separated by newlines (trying both unix style and windows style newlines). This results in the creation of a new value for the field that combines the specified values, changing the newlines to spaces.
3. Using the same custom field ID multiple times in the customFields array, once for each value needed. This results in a "bad request" error also.
I'm out of ideas.