g1smd - 12:04 pm on Feb 20, 2013 (gmt 0)
(.*) is not an "option". It's a regular expression looking at the path part of the URL request. It means "match any character, zero or more times. To match more "specific" requests, you replace with .* with a more specific pattern.
The last example you gave can never work. The syntax is completely broken.
HTTP_HOST can only match hostname and no other part of the URL request. The RegEx pattern for the rule is completely missing. Move the
\/store\/(.*) bit from the Condition to the Rule and change it to
^shop/(.*) and you'll be on the way.
The target URL must not be escaped. Append /$1 to the end of the target, to re-use the captured information in the redirect.