The supply chain processes as defined in UBL end in issuing an invoice (and preferable use of a remittance advice). However there are subsequent processes involving financial institutions, such as bank payments and trade finance operations, which implicate existing business documents and involve the participation of party roles that are not documented in the UBL supply chain processes.

The UBL Payments and Finance Subcommittee is tasked with identifying requirements for the enrichment, development and implementation of standardized UBL document types for payments- and finance-related processes that have the potential to bridge UBL procurement systems to financial systems supporting the handling of payments and trade finance.

Scope of Work

1. To liaise with governments, industry, and organizations responsible for payments and trade finance to identify business and legal requirements for associated processes.
2. To develop, document and maintain the semantic conceptual models for the UBL Payment and Finance package within the UBL package as a whole. This may include identifying suitable code lists.
3. To liaise regarding the payment and finance models with other subcommittees in UBL as required.
4. To foster implementations of UBL for payment and finance through coordination, guidance, and responsiveness to queries in order to test the viability of UBL implementations in real-world scenarios. For example, the Web Payments Working Group at the W3C.
5. To develop informative materials as an aid to developers of UBL based applications and interfaces.
6. The Subcommittee is not responsible for the generation of any XML Schema.

The pace of development will attempt to keep up with the release of new versions of UBL, beginning with UBL 2.3.

List of Deliverables

1. UBL payments and finance process model(s)
2. UBL payments and finance document model(s)
3. UBL package documentation of the payments and finance models
4. Possible deliverable: Descriptions of representative payments and financing scenarios

See the full anouncement with background details here
You can join this subcomittee here