[TYPO3] Troubles using stdWrap in dam_downloads extension

[Lukas Stancik]

Hi list,

I'd like to kindly ask you for help.

I have modified dam_downloads extension (in list view) to display 
numeric value of FE user group that is set to certain files via DAM in 
BE. I would like to substitute this value with an icon to let the user 
know which files could not be seen  before logging in. It seemed that 
the easiest way is to use stdWrap. After reading the documentation and 
searching the web I have succeeded partly. I am able to display the icon 
only for all files in the list or none. This is what I have so far:

plugin.tx_damdownloads_pi1.listView.std.fe_group.if.isTrue.field = fe_group
  plugin.tx_damdownloads_pi1.listView.std.fe_group.wrap = <img 
src="icon.gif" />|

The result in FE is no icon displayed at all. If I change the first line 
to isFalse.field = fe_group then the icon is displayed every time.

Even if the fe_group value in DB is for example set to 4 the above 
condition seems to always return false. But the digit 4 is displayed 
next to the icon thanks to the wrap function.

Does anyone have a clue how to achieve my goal? Any suggestions will be 
greatly appreciated. Thanks in advance.

Best Regards

Lukas Stancik