When you say it’s a bit of a hack - I could be reading it wrong, but it looks like delete account isn’t supported out of the box and a before rule is recommended (from HTTP Operations). That’s from the VA based Web Services Connector.
However, just noticed that delete account is supported in the SaaS Web Services Connector, with the interesting note: “If you wish to exclude the default Content-Type header from the requests, please add removeDefaultHeaderFromRequest:true in the connectionParamater object”