There is an app that represents an alternative to the "Send to Cloud Connector" step in Canvases.
The use of it is quite similar to the Cloud Connector one, for doing a form submit. The main visual difference is that the configuration takes part in a pop up window within Eloqua.
This app can be used to generate an artificial form submit within a canvas, for the contacts that pass through the step. See below the configuration window. Fields can be mapped, but also Static values can be set up. The documentation is here.
The app, once installed, can be found in the canvas under the Actions menu. You can also set up a wait step and a list for contacts that have problems when being ran throught the app.