diff --git a/lib/core.js b/lib/core.js
index 969065b..4c6226d 100644
--- a/lib/core.js
+++ b/lib/core.js
@@ -165,7 +165,9 @@ module.exports.create = function (le) {
       // Certificates
       registerAsync: function (args) {
         var err;
-        var copy = utils.merge(args, le);
+        var challengeDefaults = le['_challengeOpts_' + (args.challengeType || le.challengeType)] || {};
+        var copy = utils.merge(args, challengeDefaults || {});
+        copy = utils.merge(copy, le);
         args = utils.tplCopy(copy);
 
         if (!Array.isArray(args.domains)) {