Images for custom field in sub directory

[wines]

I have a problem. I created custom image field using VM 2 administrator panel.
When I'm adding custom field to my product in "value" field I've got drop-down box with all images in /images/stories/virtuemart/products folder.

If I will create sub folder in product folder and place there images they aren't shown in this drop-down box, but i want to separate custom field images from all others images.
Ideally if  the can by displayed is such way:
/field1/test.jpg
/field1/test1.jpg
/field1/test2.jpg
/field2/prod.jpg
/field2/prod1.jpg
.....

Is there any solution or work around ?

Please help.

P.S. I'm using Joomla! 2.5 and VM 2

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