mbit, the best way to update is to take new 1.1.9 files.
THEN, take your hacked files.
OPEN: both
In the hacked files ALL the hacks are noted "Hack".
SO, you can search where the hack starts. Then copy the code, and place in the NEW file.
The category uses
product.product_category_form (thats the category from with the "tab"
ps_product_category
shop.browse
THE product uses.
product.product_form (that is the backend where you enter the keywords etc. and gives you the tab)
shop.product_details
ps_product
THE 2 form files will NEVER change, so you can always use the older versions.
The other 4 files should be copied and pasted from.
YOU just need to make sure you are pasting in the right place.
SOME of the original vmart code is commented out, and some is added to.