how do I change the tooltype to PICASSO=TRUE?
In the icon properties window, there should be two tabs. One for the icon and one for the file. Select the icon properties tab.
There should be a text area with the label "tooltypes:". If there is no entry for PICASSO in that list, then type it in, exactly as specified above.
If there is but it is set to something other than true, change it to true. If the entry has brackets around it, remove the brackets as putting any tooltype item in brackets basically removes it from the list as far as the system is concerned.
Once you've added/edited (as required) this tooltype, click save.