Redirect to subdir

[محروم.كوم]

When developing a new site it's common practice to do this in a subdir of the websever and redirect traffic to this subdir when the site is ready.
Redirection can be done in different ways, e.g. with an index.php file:
Code:

or by using .htaccess.
Code:
Options All -Indexes
RewriteEngine On
RewriteRule ^(.*)$ v2/index.php [L]
I do have the impression that not all solutions are treated the same way by search engines. Sometimes a new redirection is marked as 'temporarily moved'.

Anybody any suggestions about what is the best way to do it (from an SEO or search engine point of view). Also how not to loose ranking if redirecting to a new subdir. __DEFINE_LIKE_SHARE__