Export RIS custom

When I export from biblioscape to a RIS formatted file I notice that it omits the data in custom fields.
RIS format accepts custom fields:
C1 - Custom 1
C2 - Custom 2
C3 - Custom 3
C4 - Custom 4
C5 - Custom 5
C6 - Custom 6
C7 - Custom 7
C8 - Custom 8

So I'm not sure why the export feature omits these fields. Could you please help me customize the biblioscape export feature to include all fields that are RIS compatible.

Thank you.

Please open the file

Please open the file "C:\Biblioscape x\global\exp_refman_ris.txt". You can add more custom fields to export after:

U1  - =Custom_1
U2  - =Custom_2
U3  - =Custom_3
U4  - =Custom_4 

RefMan RIS field label on the left and Biblioscape field name on the right.