Firstly, is it a GO6 OATH or
DIGIPASS versions? It's not the same Tokens and OpenOTP only supports OATH GO6.
The inventory format is for Tokens provided by RCDEVS (for direct import into the Inventory database).
With other tokens, vendors should provide PSKC (the OATH token import standard). In OpenOTP you can import the PSKCs.
Alternatively you can register Tokens is you have the secret seeds in Hex format (without PSKC).
Note: If you have a Vasco PSKC file then you can convert it to an inventory import file with the tool /opt/webadm/openotp/bin/pkskc
Or alternatively you edit a user, choose OTP actions -> Import PSKC -> load the PKCS and choose export to inventory.