If you're sure you have at least version 8, you can try to bypass the detection.
Bonding
KÖMACEL will accept most adhesives for rigid PVC. The sheet surface must be clean, dry and free of oil or grease. When choosing an adhesive, consider the strength required, the temperature the sheet will be exposed to, cure time and environmental safety.
When bonding KÖMACEL to itself, the same solvent-type adhesives
used for rigid PVC will provide excellent results. We recommend
Lord and IPC Weldon products for most applications in which bonding
to KÖMACEL or another substrate is required. As always, we
suggest a test piece prior to full production.