As I understand, you want to show the Office documents using Office Web Apps. Instead of using the ECB actions, you want to open it using Hyperlink, am I right?
When you try to view the word document in Brower, you will get a url like this:
http://servername/_layouts/WordViewer.aspx?id=/Shared%20Documents/test.docx&source=..
In your custom Hyperlink, only the ‘id’ parameter is needed. So the link like this: http://servername/_layouts/WordViewer.aspx?id=/Shared%20Documents/test.docx.
Word: http://servername/_layouts/WordViewer.aspx?id=/Shared%20Documents/test.docx.
Excel: http://servername/_layouts/xlViewer.aspx?id=/Shared%20Documents/test.xlsx.