Does anyone know of or built a custom ADABAS adapter?

This may or may not help. At least expose an alternative to consider, if you have not already considered this.

We did several integrations with ADABAS. We considered a direct adapter development but decided to go instead with a SQL connector. The direct approach would require investing in Natural code development, which we desired to avoid. The connector exposes ADABAS to ODBC connection, which is easy for webMethods.

We used the SQL Gateway from Software AG. At the time (a few years ago) this was compared to other products and found most robust and performed best. Would be worth evaluating again.

The Gateway is not plug and play. Someone on the ADABAS side must map ADABAS structures into SQL-like tables to expose the data to an ODBC driver. This takes a little time and knowledge from an ADABAS DB Administrator. Once the Gateway is installed and the mapping is done the product works well. Use a database adapter on the webMethods side and you are integrating away.

Mark Thomsen of Alodar Systems