I'm looking for a book with in-depth coverage of creating custom tasks for SSIS, especially with regard to the user interface. What I'm specifically looking for is information on creating task properties so that they can accept expressions as well as constant values like standard task properties. It seems like chapters 14 and 15 might cover this, but I'm short on time and can't waste time going down blind alleys.

Any input would be appreciated.

It is briefly mentioned in p. 488 with custom property "MapFlags". The chapter only hints that it can be done but you got to look in MSDN on how. Hint: research IDTSCustomProperty.