Empty Alt Text in FlexSlider

Hi,

I’m trying to get my ALT tag to populate when using the flexslider however cannot get it to work at all.

In the includes/shortcodes.php file I have changed:

$str .= ‘<span class=”img_overlay_zoom”></span>’;

to:

$str .= ‘<span class=”img_overlay_zoom”></span>’;

I then used this shortcode:

[slider][slide title="alt keywords here"]URL of image[/slide]

However the HTML code came out as:

<div class=”flexslider”><ul class=”slides”></div><li class=”pic”><span class=”img_overlay_zoom”></span>

which is obviously not valid.

Please help??