As per my extensive research (5 minutes), you cannot.
Use doSelect instead. doSelect is your best friend.
Here are the parameters i've used. I've asked for all the transitions that can happen if the current status is OP.
Notice the last one, I ask for new_status.sym as a return.
And here is the return :
<doSelectResponse xmlns="http://www.ca.com/UnicenterServicePlus/ServiceDesk">
<doSelectReturn xmlns=""><?xml version="1.0" encoding="UTF-8"?><UDSObjectList>
<UDSObject>
<Handle>cr_trans:400002</Handle>
<Attributes>
<Attribute DataType="2005">
<AttrName>new_status</AttrName>
<AttrValue>CNCL</AttrValue>
</Attribute>
<Attribute DataType="2002">
<AttrName>new_status.sym</AttrName>
<AttrValue>Annulé</AttrValue>
</Attribute>
</Attributes>
</UDSObject>
<UDSObject>
<Handle>cr_trans:400006</Handle>
<Attributes>
<Attribute DataType="2005">
<AttrName>new_status</AttrName>
<AttrValue>ASIGN</AttrValue>
</Attribute>
<Attribute DataType="2002">
<AttrName>new_status.sym</AttrName>
<AttrValue>Assigné</AttrValue>
</Attribute>
</Attributes>
</UDSObject>
<UDSObject>
<Handle>cr_trans:400462</Handle>
<Attributes>
<Attribute DataType="2005">
<AttrName>new_status</AttrName>
<AttrValue>RE</AttrValue>
</Attribute>
<Attribute DataType="2002">
<AttrName>new_status.sym</AttrName>
<AttrValue>Résolu</AttrValue>
</Attribute>
</Attributes>
</UDSObject>
</UDSObjectList>
</doSelectReturn>
</doSelectResponse>
Hope this helps