diff --git a/cic/ext/eth/__init__.py b/cic/ext/eth/__init__.py
index 881dd09..0a84b82 100644
--- a/cic/ext/eth/__init__.py
+++ b/cic/ext/eth/__init__.py
@@ -9,7 +9,11 @@ from chainlib.eth.tx import (
         TxFactory,
         )
 from chainlib.eth.connection import RPCConnection
-from chainlib.eth.contract import ABIContractEncoder
+from chainlib.eth.contract import (
+        ABIContractEncoder,
+        ABIContractType
+        )
+from chainlib.eth.address import is_address
 from eth_token_index import TokenUniqueSymbolIndex
 from eth_address_declarator import Declarator
 
@@ -39,24 +43,88 @@ class CICEth:
             self.tx_format = TxFormat.RLP_SIGNED
 
 
-    def prepare_token(self, name, symbol, precision, code, extra={}, positions=None):
+    def prepare_token(self, name, symbol, precision, code, extra=[], extra_types=[], positions=None):
         self.token_details = {
                 'name': name,
                 'symbol': symbol,
                 'precision': precision,
                 'code': code,
                 'extra': extra,
+                'extra_types': extra_types,
                 'positions': positions,
                 }
 
+    
+    def __detect_arg_type(self, v):
+        typ = None
+        try:
+            int(v, 10)
+            typ = ABIContractType.UINT256
+        except TypeError:
+            pass
+   
+        if typ == None:
+            try:
+                vv = strip_0x(v)
+                if is_address(vv):
+                    typ =  ABIContractType.ADDRESS
+                else:
+                    typ =  ABIContractType.BYTES32
+            except ValueError:
+                pass
+
+        if typ == None:
+            try:
+                v.encode('utf-8') 
+                typ =  ABIContractType.STRING
+            except ValueError:
+                pass
+
+        if typ == None:
+            raise ValueError('cannot automatically determine type for value {}'.format(v))
+
+        logg.info('argument {} parsed as abi contract type {}'.format(typ.value))
+
+        return typ
+
+
+    def __order_args(self):
+        args = [
+                self.token_details['name'],
+                self.token_details['symbol'],
+                self.token_details['precision'],
+                ]
+        args_types = [
+                ABIContractType.STRING.value,
+                ABIContractType.STRING.value,
+                ABIContractType.UINT256.value,
+                ]
+
+        for i, x in enumerate(self.token_details['extra']):
+            args.append(x)
+            typ = None
+            if self.token_details['extra_types'] != None:
+                typ = self.token_details['extra_types'][i]
+            else:
+                typ = self.__detect_arg_type(x)
+            arg_types.append(typ)
+
+        positions = self.token_details['positions']
+        if positions == None:
+            positions = list(range(len(args)))
+       
+        return (args, args_types, positions)
+
 
     def process_token(self):
-        enc = ABIContractEncoder()
-        enc.string(self.token_details['name'])
-        enc.string(self.token_details['symbol'])
-        enc.uint256(self.token_details['precision'])
-        code = self.token_details['code'] + enc.get()
+        (args, args_types, positions) = self.__order_args()
 
+        enc = ABIContractEncoder()
+
+        for i in positions:
+            getattr(enc, args_types[i])(args[i]) 
+
+        code = self.token_details['code'] + enc.get()
 
         signer_address = self.resources['token']['key_address']
         c = TxFactory(self.chain_spec, signer=self.signer, nonce_oracle=self.nonce_oracle, gas_oracle=self.fee_oracle)
@@ -76,6 +144,7 @@ class CICEth:
         self.outputs.append(r)
         return r
 
+
     def process_token_index(self):
         c = TokenUniqueSymbolIndex(self.chain_spec, signer=self.signer)