Ok, I’ve got the workaround – you just need to do the following to make /archives/year/month/post_id permalinks work:
1) Allow WP to generate a .htaccess.
2) In that .htaccess file, remove the rewrite rules that take /year/month/day, /year/month/day/feed, /year/month/day/paged. There should be 4 of these rules altogether.
3) There should be 5 rules left now before the /IfModule tag. In those rules, you should remove one of the paired instances of ([0-9]{1,2})/, then remove &day=$3, and renumber the remaining parameters accordingly.
You’ll end up with the following:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /blog/
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^.*$ - [S=35]
RewriteRule ^feed/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?&feed=$1 [QSA,L]
RewriteRule ^(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?&feed=$1 [QSA,L]
RewriteRule ^page/?([0-9]{1,})/?$ /blog/index.php?&paged=$1 [QSA,L]
RewriteRule ^comments/feed/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?&feed=$1&withcomments=1 [QSA,L]
RewriteRule ^comments/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?&feed=$1&withcomments=1 [QSA,L]
RewriteRule ^comments/page/?([0-9]{1,})/?$ /blog/index.php?&paged=$1 [QSA,L]
RewriteRule ^search/(.+)/feed/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?s=$1&feed=$2 [QSA,L]
RewriteRule ^search/(.+)/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?s=$1&feed=$2 [QSA,L]
RewriteRule ^search/(.+)/page/?([0-9]{1,})/?$ /blog/index.php?s=$1&paged=$2 [QSA,L]
RewriteRule ^search/(.+)/?$ /blog/index.php?s=$1 [QSA,L]
RewriteRule ^archives/category/(.+)/feed/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?category_name=$1&feed=$2 [QSA,L]
RewriteRule ^archives/category/(.+)/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?category_name=$1&feed=$2 [QSA,L]
RewriteRule ^archives/category/(.+)/page/?([0-9]{1,})/?$ /blog/index.php?category_name=$1&paged=$2 [QSA,L]
RewriteRule ^archives/category/(.+)/?$ /blog/index.php?category_name=$1 [QSA,L]
RewriteRule ^archives/author/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?author_name=$1&feed=$2 [QSA,L]
RewriteRule ^archives/author/([^/]+)/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?author_name=$1&feed=$2 [QSA,L]
RewriteRule ^archives/author/([^/]+)/page/?([0-9]{1,})/?$ /blog/index.php?author_name=$1&paged=$2 [QSA,L]
RewriteRule ^archives/author/([^/]+)/?$ /blog/index.php?author_name=$1 [QSA,L]
RewriteRule ^archives/([0-9]{4})/feed/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?year=$1&feed=$2 [QSA,L]
RewriteRule ^archives/([0-9]{4})/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?year=$1&feed=$2 [QSA,L]
RewriteRule ^archives/([0-9]{4})/page/?([0-9]{1,})/?$ /blog/index.php?year=$1&paged=$2 [QSA,L]
RewriteRule ^archives/([0-9]{4})/?$ /blog/index.php?year=$1 [QSA,L]
RewriteRule ^archives/([0-9]{4})/([0-9]{1,2})/feed/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?year=$1&monthnum=$2&feed=$3 [QSA,L]
RewriteRule ^archives/([0-9]{4})/([0-9]{1,2})/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?year=$1&monthnum=$2&feed=$3 [QSA,L]
RewriteRule ^archives/([0-9]{4})/([0-9]{1,2})/page/?([0-9]{1,})/?$ /blog/index.php?year=$1&monthnum=$2&paged=$3 [QSA,L]
RewriteRule ^archives/([0-9]{4})/([0-9]{1,2})/?$ /blog/index.php?year=$1&monthnum=$2 [QSA,L]
RewriteRule ^archives/([0-9]{4})/([0-9]{1,2})/([0-9]+)/feed/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?year=$1&monthnum=$2&p=$3&feed=$4 [QSA,L]
RewriteRule ^archives/([0-9]{4})/([0-9]{1,2})/([0-9]+)/(feed|rdf|rss|rss2|atom)/?$ /blog/index.php?year=$1&monthnum=$2&p=$3&feed=$4 [QSA,L]
RewriteRule ^archives/([0-9]{4})/([0-9]{1,2})/([0-9]+)/page/?([0-9]{1,})/?$ /blog/index.php?year=$1&monthnum=$2&p=$3&paged=$4 [QSA,L]
RewriteRule ^archives/([0-9]{4})/([0-9]{1,2})/([0-9]+)/?([0-9]+)?/?$ /blog/index.php?year=$1&monthnum=$2&p=$3&page=$4 [QSA,L]
RewriteRule ^archives/([0-9]{4})/([0-9]{1,2})/([0-9]+)/trackback/?$ /blog/index.php?year=$1&monthnum=$2&p=$3&tb=1 [QSA,L]
</IfModule>
Year/month/day permalinks will not work as a result of this change.
