Lpc2000

I am planning to use the secondary JTAG (LPC2104) in a design.  I 
have already been debugging (from flash) using the second JTAG by 
placing a firmware in flash to enable the second JTAG pins and then 
starting the debugger.
So, in the actual application, I will have to load the JTAG enable 
firmware everytime(via ISP)I want to debug or program via the 2nd 
JTAG port, correct?
I have dip switches in the design, could I use one of these to 
trigger software to write to PINSEL1 and enable the 2nd JTAG?

Thanks

Rich