Can I pass a parameter to a mapping without using a process flow?

Question

I have to load data from multiple countries at different times. Rather than creating an individual mapping for each country, I want to create 1 mapping and pass the country code as a parameter to the mapping. I tried to use an input parameter in the mapping and add a custom parameter to the sqlplus_exec_template hoping the custom parameter would pass to the mapping input parameter but it's not working. No data loads.
When I add a default value to the input parameter, the data loads but this isn't the solution I need. The value of the parameter will vary depending on the country so I can't use defaults. Since the mappings load automatically, I need the script to be able to pass the parameter in.
I'm trying to avoid going through a process flow because that just seems like overkill for what I need to do. I just want to load all the data where country code = 'X'. Is this even possible?

Answer 1

o.k. I tried everything to see which would be the best scenario.
Zeppo - I can't use your solution because ".main", I believe, applies to an older version of OWB. We have 10g. I know in 3.1 ".main" applies because I still have mappings from that version. Doesn't apply to 10g.
Sutirtha - I set the property for the prompt but it still didn't work.
MccM - Yes, the premapping process works perfectly. Only thing is that I have to come up with so many different scenarios in the If then else logic. Giving me a migraine ...
.... so ....
I punked out and created a table that stores all of the load times by country code. In the joiner, I linked the table's country code to the country code in my view and only retrieved data where the table's load hour equals the sysdate hour. Now all I have to do is change an entry in the working table if I need to reschedule a load.
It's cluggy but it works ... and I met me goal of only using 1 mapping.
Thanks to all of you for providing your input. Much appreciated.