I managed to do this by doing the following....
Create an Insert and Update page as usual using the wizard.
Then save the update page as a clone page.
Then click the Update Record Server Behaviour which highlights the update code.
Do the same on the Insert page and copy the code.
Paste the code over the update code in the clone page.
Do the same to change the Update button to an Insert button.
Then create a link to the clone page in the same way that you would the update page (just change the file name)