Currently, there is no option to change the separator. This is something we plan to add in the next few weeks.
In the meantime, you can use the new "Parse" pluing under "Miscellaneous", in the following way:
For number, date and date and time elements in your structure, you can add a property 'format' and specify the number or date format for the conversion (the format should go into the local property value)
For best results, use the Firefox browser..