Hi vijetha, I wonder if the Inject Http Header global filter will work for you? You can review this link to see:
Inject HTTP Header - DevTest Solutions - 9.1 - CA Technologies Documentation
This filter lets you replace a header in an HTTP call. When the header does not exist, a new header is added. You can also specify a step to skip (for example, the login call to get the OAuth token).
I wonder if you can place the OAuth token in this filter to make your process work? Let us know.