diff --git a/src/pretixbase/migrations/0005_auto_20150212_0901.py b/src/pretixbase/migrations/0005_auto_20150212_0901.py
new file mode 100644
index 0000000000..e7534c55bd
--- /dev/null
+++ b/src/pretixbase/migrations/0005_auto_20150212_0901.py
@@ -0,0 +1,28 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+import pretixbase.models
+import versions.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0004_auto_20150211_2330'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='order',
+            name='payment_date',
+            field=models.DateTimeField(null=True, blank=True, verbose_name='Payment date'),
+            preserve_default=True,
+        ),
+        migrations.AlterField(
+            model_name='order',
+            name='payment_info',
+            field=models.TextField(null=True, blank=True, verbose_name='Payment information'),
+            preserve_default=True,
+        ),
+    ]
diff --git a/src/pretixbase/migrations/0006_auto_20150212_0908.py b/src/pretixbase/migrations/0006_auto_20150212_0908.py
new file mode 100644
index 0000000000..ebe9483260
--- /dev/null
+++ b/src/pretixbase/migrations/0006_auto_20150212_0908.py
@@ -0,0 +1,22 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+import pretixbase.models
+import versions.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0005_auto_20150212_0901'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='cartposition',
+            name='datetime',
+            field=models.DateTimeField(auto_now_add=True, verbose_name='Date'),
+            preserve_default=True,
+        ),
+    ]
diff --git a/src/pretixbase/models.py b/src/pretixbase/models.py
index e7d09c1298..baf93a4b0e 100644
--- a/src/pretixbase/models.py
+++ b/src/pretixbase/models.py
@@ -1087,10 +1087,12 @@ class Order(Versionable):
         verbose_name=_("Expiration date")
     )
     payment_date = models.DateTimeField(
-        verbose_name=_("Payment date")
+        verbose_name=_("Payment date"),
+        null=True, blank=True
     )
     payment_info = models.TextField(
-        verbose_name=_("Payment information")
+        verbose_name=_("Payment information"),
+        null=True, blank=True
     )
     total = models.DecimalField(
         decimal_places=2, max_digits=10,
@@ -1183,7 +1185,8 @@ class CartPosition(Versionable):
         verbose_name=_("Price")
     )
     datetime = models.DateTimeField(
-        verbose_name=_("Date")
+        verbose_name=_("Date"),
+        auto_now_add=True
     )
     expires = models.DateTimeField(
         verbose_name=_("Expiration date")