[Typo3] Making extensions, which use XCLASS - some problems

[tapio]

Hi

But I didn't get XCLASS-implementation to work as desired.
I need to modify two core files.

I tried to overwrite some function with these

$TYPO3_CONF_VARS["BE"]["XCLASS"]["typo3/alt_doc.php"] = 
t3lib_extMgm::extPath($_EXTKEY) . 'class.ux_sc_alt_doc_tm.php';
$TYPO3_CONF_VARS["BE"]["XCLASS"]["typo3/sysext/cms/layout/db_layout.php"] 
= t3lib_extMgm::extPath($_EXTKEY) . 'class.ux_sc_db_layout.php';

I have *two* problems:

1) 'class.ux_sc_alt_doc_tm.php' caused that 'erotea_date2cal' stopped 
working. That plugins use also XCLASS and it adds an extension class for 
the same class. I found that in one installation 'erotea_date2cal' 
didn't work. Presumably it conflicts with another plugin, which use 
XCLASS-implementation.

2) 'class.ux_sc_db_layout.php' seems not to work at all. That didn't 
work either when I tried to fix 'erotea_date2cal' (see the topic ' 
Trying to fix the plugin 'erotea_date2cal' in the 'dev' list). The 
problem relates presumably the fact that 'db_layout.php' is a part of 
the plugin 'cms'. Should I try to set XCLASS for some other file?