Right this moment no, but I can turn it into a plugin (hopefully) or write up a small guide on what needs to be edited to make it happen. Look for that to happen tomorrow probably.
Here's the solution. In /plugins/import_manager/components/migrators/whmcs/whmcs_migrator.php change:
if (version_compare(BLESTA_VERSION, "3.1.0", ">=")) {
To:
if (version_compare(BLESTA_VERSION, "3.1.0-b1", ">=")) {
This fix will be included in 3.1.0 (CORE-969).