Support importing into a custom field with multiple contexts / configuration schemes

I'm attempting to import from CSV into a custom field that has 2 contexts defined: context A and context B. The importer fails to import into the defined custom field, and instead creates a new instance of the custom field. Here is the log message:

2012-08-06 16:33:25,725 WARN - Custom field 'Impacted Silos' has multiple configuration schemes.
2012-08-06 16:33:25,726 WARN - Importer is unable to extend custom field context automatically.
2012-08-06 16:33:25,726 INFO - Custom field not found. Creating a new custom field for [FOO, BAR],com.atlassian.jira.plugin.system.customfieldtypes:multiselect,com.atlassian.jira.plugin.system.customfieldtypes:multiselectsearcher,Impacted Silos

Is there a workaround for this? Isn't it possible to derive which context should be used by looking at the Issue Type, which is specified in the CSV file. In my case, context A is applicable for Issue Types "Task" & "Sub-task", whereas context B is application for (custom) Issue Type "Memo".