The short answer is that it can't be done.
For those who are familiar with databases, here's the long answer:
Apparently the Organizer's Search bar only sends a SQL query to the metadata_string_table table.
I looked at the database tables, and the metadata_string_table table only contains metadata values whose content is a string. There is another table -- the metadata_integer_table -- that only contains metadata values whose content is an integer. IOW, the metadata_string_table table only contains metadata whose description_id refers to an id value in the metadata_description_table table whose data_type is a "string_type". Similarly, the metadata_integer_table table only contains metadata whose description_id refers to an id value in the metadata_description_table table whose data_type is an "integer_type". Among other metadata items, the ISO Speed is defined in the metadata_description_table table as an "integer_type".
Thus, you can type a search term in Organizer's Search box to look for "make:" or "model:" or "author:" because those data types are strings, but not a search for "ISOSpeedRatings" because that data type is an integer. When you use Find...By Details (Metadata) to look for items with an ISO Speed of > 1600, the code is using a SQL query that does a join including the metadata_integer_table to return the results. Unfortunately, there's no way within Organizer to manually built that kind of custom SQL query.
Ken
