Yes, that's possible. However, we need to make some adjustments to your account settings on our end and you will also need some additional software from us. If this hasn't been set up yet and you are interested, you can email support@validsign.nl. Once everything is set up, you can set up signing with a certificate in the following way:
You go to the transaction (or create a new transaction) for which you want to set up a signer with a certificate. Then, next to the signer, you click on "Settings".
Then, under "Signing method", you can set that this signer should sign with a personal certificate. For a certificate on a physical token, you can choose Personal Certificate Signing, for a Cloud certificate you can choose Qualified cloud signing.