1) see the Get ( TriggerKeystroke ) function
2) Try "*" & TypeAheadGlobal::gSearchValue & "*"
as your criteria
3) Use Set Error Capture [on] to supress the error dialog.
Here is a thread of scripted find examples that you may find useful: Scripted Find Examples
You might also find the search portals in this demo file of interest:https://www.dropbox.com/s/0pm1gdqcfi2ndpv/EnhancedValueSelection.fp7