Trouble changing the cpu core count/memory for VMware service catalog item


I can’t seem to figure out how to change the cpu core count and amount memory for a VMware service catalog item.
The CPU core count are 1 2 4 8 and I need also 6. Also the option for 48Gb of RAM is missing.
In Automate -> Customization -> Provisioning Dialogs -> VM Provision I can seem to find anything to edit. Does this section applies also to services or just to VMs provisioning requests from Compute -> Infrastructure ?

Thank you.