Variable width with $INFO



Hi all. Can anyone tell me why my ListItems Property does not work for a width field?:

Does not work:

Code:
                    <control type="image">
                        <left>700</left>
                        <top>5</top>
                        <height>20</height>
                        <width>$INFO[ListItem.Property(percentage)]</width>
                        <texture colordiffuse="FF12B2E7">colors/grey.png</texture>
                        <bordertexture border="10" infill="false"></bordertexture>
                    </control>

However, the label Control just below it shows the right number between 0-100 followed by a %:

Code:
                    <control type="label">
                        <left>700</left>
                        <top>5</top>
                        <width>100</width>
                        <height>20</height>
                        <label>$INFO[ListItem.Property(percentage)]%</label>
                        <font>font9</font>
                        <align>center</align>
                        <aligny>center</aligny>
                    </control>

I am trying to realize a simple bar that indicates the signal strength of an wifi. My idea was an image Control with max 100 witdh filled to whatever the signal strength is between 0-100. So for example if it is 90 it is almost fully filled, if it is 10, its only a small bar….
Thanks for any hint!