Unexpected non-secure transfer in https protocol (IE7 + IE8)

Hello Team,

we upgraded to JIRA 4.4.3 and encountered an issue: During the https transfer we suddenly got warning, that JIRA will display some information obtained by unsecure transfer.
This happens in the IE7+8 (should be supported by JIRA 4.4.x).
Steps to reproduce:

Log in
In the menu bar expand the submenu Projects
Select All projects
Here we receive the warning message.
There are many more occurences, suh as filtering in Issue Navigator etc.

We found out that this is probably caused by calling res://ieframe.dll/navcancl.htm (see screenshot from the Temporary Internet Files related to that https call).
The navcancl.htm contains links to some icons, which are not delivered by https - and this causes the whole issue. See attached the navcancl.htm file.

Is there any way how to prevent this - anything else than upgrade to newer version of IE or using different browser? (Security policy).

This is very annoying...

Thank you,
Zdenek