SuccessFactors Employee Central Payroll

Hi,

Understand that we cant make much of customization to SF EC Payroll, if a customer wants to migrate to SF EC Payroll and have quite a bit of customization to schema/rule/functions in on-premise payroll how to go about in this scenario.

If the customer want(s) to keep all the existing customization in SF EC Payroll too is this possible ?

Thanks,

Sriram