On the same device (All-In-One), it is possible to activate the payment terminal button directly from the POS system by providing the necessary activation data from the viva portal, which you can find below:

Log in to to the viva.com portal
Select Settings -> API IDs

Copy Client ID

Create a Secret ID and copy it. The Secret will only be shown once and any existing ones will stop working when you create a new one.

Email your IDs to customer support

You can then activate the new terminal by selecting Activation in the Settings menu of the Solmio Cashier application -> Viva terminal opens and you can select the terminal-specific settings.