Multilingual sitemaps contain identical content

Problem/Motivation

I have setup a bilingual site with separate domains for each language. I have created one page and its translation. When viewing the different XML sitemaps created in each domain I observe that the content is identical and they only contain the English page. Additionally, the default URL of the site is used in both XML sitemaps. In other words - the Spanish XML sitemap, which sits at the correct URL, is the same as the English one.

Detail/Steps to Reproduce
Brand new site with following core and modules:
Drupal 6.22
XML Sitemap 6.x-2.0-beta3
Admin menu 6.x-1.8
Internationalization 6.x-1.9

- I installed Drupal with a default language of English and have added the Spanish language.
- I configured the language negotiation as 'Domain path only'
- I added the different domains for each language
- Content selection mode is set to 'only current language'
- I created a new content type, multilingual settings set to 'enabled with translation' and content is in XML sitemap
- I created the two pages
- I setup two XML sitemaps and explicitly set the language to the desired language
- I flushed all caches and rebuilt the XML sitemaps / ran cron.

The resultant sitemaps, as summarised above:
- Contain the default URL for the link (page created earlier)
- Contain only the English language URL
- Exist at the desired URL (i.e. at 'default' domain name and Spanish language domain name

Any assistance in resolving this issue would be greatly appreciated. Naturally I read through the current support issues but could not find anyone with an identical issue to mine. I apologise if this a duplicate of an issue I have missed.

Regards

Adam