Hi Simon,
Yes you can. Please, make sure if this is vendor has the role that can be identified as it like a customer. Normally, by BP transaction you can see this role.
The BP was used because this scenario. Since 6.0 version, the vendor can be customer and customer can be vendor by using unique code or BP number.
Please, check the documentation below:
Customer/Vendor Integration - Business Partners - SAP Library
JPA