Proxoid doesn't support subversion methods. The workaround on Linux is simple: use proxychains!

Install proxychains

sudo apt-get install proxychains

Setup your proxychains.conf

mkdir ~/.proxychains
gedit ~/.proxychains/proxychains.conf

Paste this into the text editor

DynamicChain
tcp_read_time_out 15000
tcp_connect_time_out 10000
[ProxyList]
http 127.0.0.1 8080

Now instead of running

svn up

run

proxychains svn up

Done!