diff --git a/mvpa2/measures/rsa.py b/mvpa2/measures/rsa.py
index 89537e9bfe..c54bacddb6 100644
--- a/mvpa2/measures/rsa.py
+++ b/mvpa2/measures/rsa.py
@@ -267,6 +267,10 @@ def __init__(self, X, pairwise_metric='correlation', center_data=False,**kwargs)
         for i in range(m):
             X[i,:] = rankdata(X[i,:])
 
+        if isinstance(X, np.matrix):
+            self.X = X        
+        else:
+            self.X = np.matrix(X)
         self.pairwise_metric = pairwise_metric
         self.center_data = center_data
 
@@ -293,7 +297,7 @@ def _call(self,ds):
         b[np.isnan(b)] = 0
 
 
-        return Dataset(b)
+        return Dataset(np.asarray(b))