The Access Support Portal bases many of its actions on the product selected by the user, and will remember the last product chosen or default to one, depending upon the action being started.
To raise a case with the correct product pre-selected:
Log in to the support portal.
Click the All products drop-down beneath "What would you like help with today?".
Select the relevant Access product.
Click Create a case.
Follow on-screen prompts and fill out the fields presented; any product-specific drop-down field should show options related to the product chosen in step 3.
Complete case creation.