How do I get the new petrol pipe into the tank? McCullock Trimmac 250 ls?

Hi, The petrol pipes had perished on my McCullock 250 ls strimmer, so rather than do a passable impression of fireball XL5 I thought I'd replace them!
I have taken the tank off and have stripped it down ready for the new pipes.
My question is how do you get the new pipes through the holes in the tank? I'm probably being really thick but then I am a girlie!
Thanks in advance for any help on this one.
Ness x