IEEEtran bibliography url accessdate

I want to modify the line of text which comes before an url when you add a url to your bibliography item.

The default format for the url is

FUNCTION {format.url}
{ url empty${ "" } { this.to.prev.status this.status.std cap.yes 'status.cap := name.url.prefix " " * "\url{" * url * "}" * punct.no 'this.status.punct := punct.period 'prev.status.punct := space.normal 'this.status.space := space.normal 'prev.status.space := quote.no 'this.status.quote := } if$
}


Now I removed name.url.prefix " " * and replaced it with

accessdate empty${ "[Online]. Available: " * } { "[Online; accessed: " * accessdate * "]. Available:" * } if$


And added accessdate to the set if ENTRY items. When I however now compile it I get the error:

You can't pop an empty literal stack for entry BIBLIOGRAPHY ITEM

What is the problem here? I noticed that as soon as I add the line name.url.prefix " " * back everything works again, also in combination with my added code. I tried removing everything which was associated with name.url.prefix but that did not work helas.

Minimal example IEEEtran.cls needed:

document.tex

\documentclass[journal]{IEEEtran}
\usepackage{cite}
\usepackage{url}
\begin{document}
Test \cite{stackexchange}.
\bibliographystyle{IEEEtran}
\bibliography{IEEEabrv,bibliography}
\end{document}


Bibliography.bib

@misc{stackexchange,
title="Title",
author="Author",
year="2014",
publisher="Someone",
url="http://tex.stackexchange.com/",
accessdate="2014-11-04"
}


Modified IEEEtran.bst

http://pastebin.com/VQa7V4bx

The url function is on line 1938 and name.url.prefix is used in multiple lines.