asp.net mvc - "%" character causing issues in IIS URL rewrite regex -

i'm replatforming online shop, , part of process writing 301 redirects old links customers may have bookmarked hit new addresses. of them work apart ones in old address contains % character. seems somehow interfering regex. rule is:

<rule name="custom 41 redirect" stopprocessing="true">   <match url="^c80/how-to-%20use-shop-name\.aspx" ignorecase="true" />   <action type="redirect" url="/how-to-use-shop-name" redirecttype="permanent" /> </rule> 

testing using built in regex tester in iis tells me hitting

/c80/how-to-%20use-shop-name.aspx

matches pattern, yet rule fails redirect me when hit address.

i should stress there 400 rewrites in web.config, 3 contain % character break.

since string tested against regex url-decoded, no longer need %20 in regex. use plain space:

<match url="^c80/how-to- use-shop-name\.aspx" ignorecase="true" /> 

also, in case space optional, may use ? after it:

<match url="^c80/how-to- ?use-shop-name\.aspx" ignorecase="true" />