I am familiar with these types of solutions, but because I'm most familiar with those that my company, Paymetric, provides I am trying hard not to seem like I'm only responding to promote my company's products.
That said, your question about SAP providing the "hooks" is a great question. As far as I've been able to determine in 20 years working with SAP's solutions, the only "hooks" I'm familiar with are the ones for encrypting credit card numbers. Because that integration wasn't initially applicable to all instances of credit card related fields in all SAP database tables, we started adding a custom integration point through the use of Conversion Exits at the Domain level or in Search Helps at the Data Element level.
This approach allows you to integrate to an external tokenization service from essentially any specific field you wish. And by integrating at the Domain or Data Element level the integration applied across all tables where that Domain or Data Element is referenced.
I'd love to find out if anyone is aware of a more elegant approach to integration, because we're seeing an increasingly large interest in tokenizing PII data and would prefer to use a standard SAP interface. But I'm not aware of a standard interface, only this custom integration approach.
