Light Installer Script (LIS) - DiskSpan_GUI

[-tara]

After getting the diskspan output of 2 files (data1.bin,data-optional.bin) and adding both to the records.ini like so:

[Record1]
Type=FreeArc_Original
Source={src}\data1.bin
Output={app}\
Disk=1
Size=1.924.677.867 bytes

[Record2]
Type=FreeArc_Original
Source={src}\data-optional.bin
Output={app}\
Disk=2
Size=78.614.874 bytes

i merge the records.ini into the setup.dll and include the setup.dll in innosetup, although im not sure how to "tag" the optional file as such, therefore when i try installing without the optional file the setup asks for it.
How do i make the installer skip the optional file if its not there?
Thanks in advance.