Search Service Application: Access Denied

The context:

• One server with SharePoint and MSSQL Express 2008 R2
• SharePoint Foundation 2010 SP1
• Search Server Express 2010 SP1
• Claim Authentication activated

My Problem:

• Got an error message when I want to manage the Search Service Application in Central Administration

Work around:

Log into Central Administration with the Farm Account and you will not have the error message.

If the Farm Account is "Network Service" (you can check it in Central Administration \Service Accounts), then you could do the following:

1. Create a new local or domain(*) account called "MegaFarmAccount" and add in the local Administrators group
2. Go to Central Admin (Central Administration \ Managed Accounts ) and add this account as "Managed Account"
3. Go to Central Administration \ Service Accounts and set this account as the Farm Account
4. Go to Central Administration \ Web Applications Management, select the web application you have to crawl, click on the User Policy icon in the Ribbon, then add your new account (all zone) with "Full Read - Has full read-only access"
5. Go to Central Administration \ Search Service Application: Search Administration  and change the Default content access account by your new account
6. Log into Central Administration with "MegaFarmAccount" and you will not have the error message

(*) must be a domain account if you want to use the Domain Active Directory authentication. If you use a local account, you will only be able to pick local users, not Domain AD users when managing the security in your SharePoint websites.
However, I created an account in my Domain AD with the same name & pwd as my local account previously created ("MegaFarmAccount"),  and I noticed that my websites were able to pick users from the AD.
If I disable the domain account "MegaFarmAccount", the websites cannot contact the AD.