diff --git a/ChangeLog b/ChangeLog
index 2338f5e..6151d62 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2004 Apr 19 Stefan Urbanek
+
+    * applied patch from Mateu Batle to replace nil valuse with STNil on 
+    message sending
+    * fixed STConversation issue
+    
 2004 Mar 28 Stefan Urbanek
 
     Changes according to the Helge Hess:
diff --git a/Frameworks/StepTalk/STConversation.m b/Frameworks/StepTalk/STConversation.m
index b4371b8..f731c66 100644
--- a/Frameworks/StepTalk/STConversation.m
+++ b/Frameworks/StepTalk/STConversation.m
@@ -79,8 +79,9 @@
 - initWithEnvironment:(STEnvironment *)env 
              language:(NSString *)langName
 {
-    [self subclassResponsibility:_cmd];
-    return nil;
+    [self dealloc];
+    
+    return [[STConcreteLocalConversation alloc] initWithEnvironment:env language:langName];
 }
 
 - (void)setLanguage:(NSString *)newLanguage
diff --git a/Frameworks/StepTalk/STScriptObject.m b/Frameworks/StepTalk/STScriptObject.m
index 64edc72..6d96583 100644
--- a/Frameworks/StepTalk/STScriptObject.m
+++ b/Frameworks/StepTalk/STScriptObject.m
@@ -2,9 +2,10 @@
 
 #import "STScriptObject.h"
 
-#import "STEngine.h"
-#import "STObjCRuntime.h"
 #import "NSInvocation+additions.h"
+#import "STEngine.h"
+#import "STExterns.h"
+#import "STObjCRuntime.h"
 
 #import <Foundation/NSArray.h>
 #import <Foundation/NSCoder.h>
@@ -141,7 +142,15 @@ some other, more clever mechanism. */
     for(index = 2; index < count; index++)
     {
         arg = [invocation getArgumentAsObjectAtIndex:index];
-        [args addObject:arg];
+
+        if (arg == nil)
+        { 
+            [args addObject:STNil];
+        }
+        else 
+        { 
+            [args addObject:arg];
+        } 
     }
 
     retval = [engine executeMethod:method
diff --git a/Languages/Smalltalk/STSmalltalkScriptObject.m b/Languages/Smalltalk/STSmalltalkScriptObject.m
index b4a7b6f..f4087f3 100644
--- a/Languages/Smalltalk/STSmalltalkScriptObject.m
+++ b/Languages/Smalltalk/STSmalltalkScriptObject.m
@@ -158,7 +158,15 @@
     for(index = 2; index < count; index++)
     {
         arg = [invocation getArgumentAsObjectAtIndex:index];
-        [args addObject:arg];
+
+        if (arg == nil)
+        {
+            [args addObject:STNil];
+        }
+        else 
+        {
+            [args addObject:arg];
+        }
     }
 
     // NSDebugLLog(@"STSending",
@@ -168,7 +176,7 @@
                               forReceiver:self
                                 arguments:args];
     RELEASE(args);
-
+    
     // NSDebugLLog(@"STSending",
     //            @"<< returned from forwarding");