animation in wml or XHTMl-mp

hi
i am currently working on wap application in which i want
to move image horizantilly & vertically but at that movement
i am not make it possible so i want to help on this topic
from someone if anybody knows how to done then plz
send me reply.
i have also assign variable value to hspace & vspace attribute
in image tag just like this
<img src="logo.wbmp" hspace="$(hs)" vspace="$(vs)">
but i get error

wml encoder:invalid length as attr.value
thanks in advance if u think or give suggestion to me