diff --git a/slic/core/acquisition/broker_client.py b/slic/core/acquisition/broker_client.py
index 6409f625..02053f77 100644
--- a/slic/core/acquisition/broker_client.py
+++ b/slic/core/acquisition/broker_client.py
@@ -298,11 +298,12 @@ class BrokerError(Exception):
 
 class BrokerConfig:
 
-    def __init__(self, pgroup, rate_multiplicator=1, append_user_tag_to_data_dir=False, client_name=None):
+    def __init__(self, pgroup, rate_multiplicator=1, append_user_tag_to_data_dir=False, client_name=None, **kwargs):
         self.pgroup = pgroup
         self.rate_multiplicator = rate_multiplicator #TODO: can we read that from epics?
         self.append_user_tag_to_data_dir = append_user_tag_to_data_dir
         self.client_name = client_name
+        self.kwargs_init = kwargs # unknown arguments will be forwarded verbatim to the broker
         self.set(None) #TODO: sensible defaults?
 
     def set(self, output_dir, detectors=None, channels=None, pvs=None, scan_info=None, **kwargs):
@@ -311,7 +312,7 @@ class BrokerConfig:
         self.channels = channels
         self.pvs = pvs
         self.scan_info = scan_info
-        self.kwargs = kwargs # unknown arguments will be forwarded verbatim to the broker
+        self.kwargs_set = kwargs # unknown arguments will be forwarded verbatim to the broker
 
 
     def to_dict(self, run_number, start_pulseid, stop_pulseid):
@@ -347,11 +348,11 @@ class BrokerConfig:
         if self.scan_info:
             config["scan_info"] = self.scan_info
 
-        kwargs = self.kwargs
+        kwargs = {**self.kwargs_init, **self.kwargs_set}
         if kwargs:
             header="the following unknown arguments are forwarded verbatim to the server"
             print(printable_dict(kwargs, header=header))
-            config.update(self.kwargs)
+            config.update(kwargs)
 
         return config
 
diff --git a/slic/core/acquisition/sfacquisition.py b/slic/core/acquisition/sfacquisition.py
index a61103f5..8c824dd8 100644
--- a/slic/core/acquisition/sfacquisition.py
+++ b/slic/core/acquisition/sfacquisition.py
@@ -17,7 +17,7 @@ from .detcfg import DetectorConfig
 
 class SFAcquisition(BaseAcquisition):
 
-    def __init__(self, instrument, pgroup, default_data_base_dir="static_data", default_detectors=None, default_channels=None, default_pvs=None, api_address="http://sf-daq:10002", rate_multiplicator=1, append_user_tag_to_data_dir=False, spreadsheet=None):
+    def __init__(self, instrument, pgroup, default_data_base_dir="static_data", default_detectors=None, default_channels=None, default_pvs=None, api_address="http://sf-daq:10002", rate_multiplicator=1, append_user_tag_to_data_dir=False, spreadsheet=None, **kwargs):
         self.instrument = instrument
         self.default_data_base_dir = default_data_base_dir
         self.spreadsheet = spreadsheet
@@ -34,7 +34,7 @@ class SFAcquisition(BaseAcquisition):
         self.default_channels  = default_channels
         self.default_pvs       = default_pvs
 
-        self.client = BrokerClient(pgroup, address=api_address, rate_multiplicator=rate_multiplicator, append_user_tag_to_data_dir=append_user_tag_to_data_dir, client_name="slic")
+        self.client = BrokerClient(pgroup, address=api_address, rate_multiplicator=rate_multiplicator, append_user_tag_to_data_dir=append_user_tag_to_data_dir, client_name="slic", **kwargs)
 
         self.current_task = None