[TYPO3] Typo3 4.0 install: problem with extension that requires the symlinks

[Pieter]

I'm running a first 4.0 test on a WinXP system.  The extension 
beko_debugster is installed on this system.  The backend does not load 
but shows the error:
Warning: main(C:/apache/xampp/htdocs/t4/tslib/class.tslib_pibase.php): 
failed to open stream: No such file or directory in 
C:\apache\xampp\htdocs\t4\typo3conf\ext\beko_debugster\pi1\class.tx_bekodebugster_pi1.php 
on line 25

So, i made a copy of tslib to C:/apache/xampp/htdocs/t4/ and ... YES, 
the backend was working.

But, the fronted now pops up with an error:
Fatal error: Cannot redeclare class tslib_pibase in 
C:\apache\xampp\htdocs\t4\typo3\sysext\cms\tslib\class.tslib_pibase.php 
on line 0

I can uninstall beko_debugster or I can change the source of 
beko_debugster but there are probably more extensions with the same 
problem.  What is the best way to prevent these problems?  What should I 
do to simulate the pre-4.0 symlinks (on a WinXP and probably also on a 
Linux system)?

Regards,
Pieter