Can I link my custom web item (Button) to a Jira Screen?

[Dylan Chrispin]

I have created a custom web item in the form of a button using script fragments.

I require this button when clicked to load a Jira screen that is not set to any of the default actions (Create, Edit or View). 

In theory this shouldn't be too hard as the feature described works with workflow transitions however I can not seem to get anything to work or find anything on the internet.

Does anybody have a solution that will allow me to link my button to a screen?