Fixing to an insulated wall can be very difficult. In this demonstration I use space-plugs to bridge the gap between the item being fixed and the external wall. Fixing to an insulated wall is much easier if you use the space plugs. Thanks to Rob from Colour republic as he has been posting about using these for years. Here is a forum post showing space plugs in use-
http://www.ultimatehandyman.co.uk/forum1/space-plugs-t69866.html
Here is a link to Colour Republic’s website- http://www.colourrepublic.co.uk/