I'm trying to create a List Button on a custom object (Test_Object__c) that is a related list to the Account object.  I've created the VF page and Controller below, but I do not get the option of adding it to a custom list button.  I am also trying to pre-populate a look-up field on Test_Object__c with the Account name.  Can anyone tell me what I am doing wrong? 

VF Page:

<apex:page standardController="Account" tabStyle="Account" extensions="TestController3">
   <apex:form >
   <apex:pageBlock >
       <apex:pageBlockSection columns="2">
            <apex:inputField value="{!L1.test1__c}"/>
            <apex:inputField value="{!L1.test2__c}"/>
            <apex:inputField value="{!L1.test3__c}"/>
       </apex:pageBlockSection>
        <apex:pageBlockButtons >
            <apex:commandButton value="Save" action="{!Save}"/>
            <apex:commandButton value="Save and New" action="{!News}"/>
            <apex:commandButton value="Cancel" action="{!cancel}"/>
        </apex:pageBlockButtons>
       </apex:pageBlock>
    </apex:form>
</apex:page>

Controller:

public class TestController3{

    public Account acct{get;set;}
    public Level_1__c L1{get;set;}

    public TestController3(ApexPages.StandardController controller) {
    
        This.L1 = (Level_1__c)controller.getRecord();
    }
    public PageReference Save(){
        L1.Company_Name__c = acct.Name;
        insert L1;
        PageReference ref = new PageReference('/'+acct.id);
        return ref;
    }
    public PageReference News(){
        return null;
    }
    public PageReference Cancel(){
        return null;
    }
}