Errors on server side when exporting PDF and using HTTPS

Environment: Tomcat + hsqldb. No httpd, no squid, no proxies. Only HTTPS setup
Steps to reproduce:

-login on the wiki using HTTPS.
-Try exporting Main.WebHome or any other page that includes images bundled with the platform.

You will get a stacktrace:

2011-06-08 13:23:54,780 https://192.168.2.50:8443/xwiki/bin/export/Main/WebHome?format=pdf ERROR FOP - Error with opening URL 'https://192.168.2.50:8443/xwiki/resources/icons/silk/book_open.gif': sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
2011-06-08 13:23:54,781 https://192.168.2.50:8443/xwiki/bin/export/Main/WebHome?format=pdf ERROR apps.FOUserAgent - Image not found. URI: https://192.168.2.50:8443/xwiki/resources/icons/silk/book_open.gif. (See position 25:585)

2011-06-08 13:23:55,157 https://192.168.2.50:8443/xwiki/bin/export/Main/WebHome?format=pdf ERROR apps.FOUserAgent - Image not found. URI: https://192.168.2.50:8443/xwiki/resources/icons/silk/book_open.gif. (No context info available)
2011-06-08 13:23:55,158 https://192.168.2.50:8443/xwiki/bin/export/Main/WebHome?format=pdf ERROR apps.FOUserAgent - Image not found. URI: https://192.168.2.50:8443/xwiki/resources/icons/silk/cog.gif. (No context info available)
2011-06-08 13:23:55,158 https://192.168.2.50:8443/xwiki/bin/export/Main/WebHome?format=pdf ERROR apps.FOUserAgent - Image not found. URI: https://192.168.2.50:8443/xwiki/resources/icons/silk/book_open.gif. (No context info available)
2011-06-08 13:23:55,159 https://192.168.2.50:8443/xwiki/bin/export/Main/WebHome?format=pdf ERROR apps.FOUserAgent - Image not found. URI: https://192.168.2.50:8443/xwiki/resources/icons/silk/cog.gif. (No context info available)
2011-06-08 13:23:55,159 https://192.168.2.50:8443/xwiki/bin/export/Main/WebHome?format=pdf ERROR apps.FOUserAgent - Image not found. URI: https://192.168.2.50:8443/xwiki/resources/icons/silk/book_open.gif. (No context info available)
2011-06-08 13:23:55,160 https://192.168.2.50:8443/xwiki/bin/export/Main/WebHome?format=pdf ERROR apps.FOUserAgent - Image not found. URI: https://192.168.2.50:8443/xwiki/resources/icons/silk/cog.gif. (No context info available)
2011-06-08 13:23:55,160 https://192.168.2.50:8443/xwiki/bin/export/Main/WebHome?format=pdf ERROR apps.FOUserAgent - Image not found. URI: https://192.168.2.50:8443/xwiki/resources/icons/silk/book_open.gif. (No context info available)
2011-06-08 13:23:55,161 https://192.168.2.50:8443/xwiki/bin/export/Main/WebHome?format=pdf ERROR apps.FOUserAgent - Image not found. URI: https://192.168.2.50:8443/xwiki/resources/icons/silk/cog.gif. (No context info available)

The problem is that getURL returns a full URL, not just a relative one, and the full links are recognized as wiki links inside the html macro