webM to Siebel integration over different OSs


We are using webMethods 6 to integrate to Siebel. The Siebel 7.5.3 app server is running on Win2k but the webMethods Integration Server is running on HP-UX. Our problem is that webMethods requires that the Siebel 3 adapter and the Siebel app server run on the same operating system.

We are reluctant to run the adapter on the same box as the app server due to very high throughput and running the adapters on separate Win2k servers will be have a hardware procurement impact.

I understand Siebel can be integrated via XML over HTTP. Do we stil get access to Siebel Business Objects? Are there other ways to integrate to Siebel?