Field in field

I have following message format.

2013-06-17 15:33:01+0200 appid="myapplication" responsetimems="155" message="Calling method="calculate" class="math" data="size="98123" rows="9811" firstcolumn="customername"""

Splunk parsed that into following fields

appid = myapplication  
responsetimesms = 155  
message = Calling method=  
class = math  
data = size=  
rows = 9811  
firstcolumn = customername

But I want to

appid = myapplication  
responsetimesms 155  
message = Calling method="calculate" class="math" data="size="98123" rows="9811" firstcolumn="customername"  
method = calculate  
class = math  
data = size="98123" rows="9811" firstcolumn="customername"  
size = 98123  
rows = 9811  
firstcolumn = customername

How can I do that?