IS does not support PUT nor DELETE when invoking an IS service. An HTTP client that tries to use those will receive an error in response. In the context of what IS is for, those actions do not make sense.
POST and GET are supported but IS tries to abstract away the difference between those two. The service that is invoked doesn’t know nor care which was used.
Might I inquire as to what you’re looking to achieve by knowing which HTTP action was used? That might help the group identify possible approaches.
#webmethods-Protocol-and-Transport#Integration-Server-and-ESB#webMethods