Software center chokes on some .deb files

Binary package hint: software-center

Using those example files that work perfectly with older software center and gdebi and dpkg
http://getax.ernstfamily.ch/downloads/GeTaxPP2009_amd64.deb
http://getax.ernstfamily.ch/downloads/GeTaxPP2010.deb

1) "<span font_desc="bold 20">Title</span>
Summary" appears as the package title

2) Clicking on "Install" button does nothing (doesn't show an error, nor installs the package).

software-center ~/Bureau/GeTaxPP2010_amd64.deb
/usr/share/software-center/softwarecenter/app.py:1114: Warning: g_object_set_qdata: assertion `G_IS_OBJECT (object)' failed
  self.window_main.show_all()
/usr/share/software-center/softwarecenter/SimpleGtkbuilderApp.py:50: Warning: g_object_set_qdata: assertion `G_IS_OBJECT (object)' failed
  gtk.main()
/usr/share/software-center/softwarecenter/view/appdetailsview_gtk.py:1093: GtkWarning: Failed to set text from markup due to error parsing markup: Erreur à la ligne 2, caractère 198 : Codage UTF-8 non valide dans le nom - « Permet la saisie informatique de votre d�claration d'imp�ts 2010. Apr�s installation, le programme est disponible dans la cat�gorie Bureautique de votre menu Applications. » n'est pas valide
  self.title.set_markup(markup)
2011-03-20 17:10:36,323 - softwarecenter.app - INFO - software-center-agent finished with status 1
2011-03-20 17:10:53,343 - softwarecenter.backend - WARNING - _on_trans_error: org.freedesktop.PolicyKit.Error.Failed: ('system-bus-name', {'name': ':1.91'}): org.debian.apt.install-file
/usr/share/software-center/softwarecenter/SimpleGtkbuilderApp.py:50: GtkWarning: Failed to set text from markup due to error parsing markup: Erreur à la ligne 2, caractère 198 : Codage UTF-8 non valide dans le nom - « Permet la saisie informatique de votre d�claration d'imp�ts 2010. Apr�s installation, le programme est disponible dans la cat�gorie Bureautique de votre menu Applications. » n'est pas valide
  gtk.main()
2011-03-20 17:11:18,311 - softwarecenter.backend - WARNING - daemon dies, ignoring: <AptTransaction object at 0x3de9d70 (aptdaemon+client+AptTransaction at 0x3750740)> exit-failed

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: software-center 3.1.23.3
ProcVersionSignature: Ubuntu 2.6.38-7.36-generic 2.6.38
Uname: Linux 2.6.38-7-generic x86_64
Architecture: amd64
Date: Sun Mar 20 17:07:32 2011
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007)
ProcEnviron:
 LANGUAGE=fr_CH:en
 PATH=(custom, no user)
 LANG=fr_CH.UTF-8
 SHELL=/bin/bash
SourcePackage: software-center
UpgradeStatus: Upgraded to natty on 2011-03-11 (8 days ago)